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Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^7 in powers of x.
(Formerly M4371 N1835)
+10
5
1, -7, 21, -35, 28, 21, -105, 181, -189, 77, 140, -385, 546, -511, 252, 203, -693, 1029, -1092, 798, -203, -581, 1281, -1708, 1687, -1232, 413, 602, -1485, 2233, -2366, 2009, -1099, 14, 1099, -2072, 2667, -2807, 2254, -1477, 0, 1057, -2346, 2744, -3017, 2457
OFFSET
7,2
REFERENCES
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
H. Gupta, On the coefficients of the powers of Dedekind's modular form, J. London Math. Soc., 39 (1964), 433-440.
FORMULA
a(n) = [x^n] ( QPochhammer(-x) - 1 )^7. - G. C. Greubel, Sep 04 2023
MAPLE
g:= proc(n) option remember; `if`(n=0, 1, add(add([-d, d, -2*d, d]
[1+irem(d, 4)], d=numtheory[divisors](j))*g(n-j), j=1..n)/n)
end:
b:= proc(n, k) option remember; `if`(k=0, 1, `if`(k=1, `if`(n=0, 0, g(n)),
(q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
end:
a:= n-> b(n, 7):
seq(a(n), n=7..52); # Alois P. Heinz, Feb 07 2021
MATHEMATICA
nmax = 52; CoefficientList[Series[(Product[(1 - (-x)^j), {j, 1, nmax}] - 1)^7, {x, 0, nmax}], x] // Drop[#, 7] & (* Ilya Gutkovskiy, Feb 07 2021 *)
Drop[CoefficientList[Series[(QPochhammer[-x] -1)^7, {x, 0, 102}], x], 7] (* G. C. Greubel, Sep 04 2023 *)
PROG
(Magma)
m:=102;
R<x>:=PowerSeriesRing(Integers(), m);
Coefficients(R!( ((&*[1-(-x)^j: j in [1..m+2]]) -1)^7 )); // G. C. Greubel, Sep 04 2023
(SageMath)
m=100; k=7;
def f(k, x): return (-1 + product( (1+x^j)*(1-x^(2*j))/(1+x^(2*j)) for j in range(1, m+2) ) )^k
def A001485_list(prec):
P.<x> = PowerSeriesRing(QQ, prec)
return P( f(k, x) ).list()
a=A001485_list(m); a[k:] # G. C. Greubel, Sep 04 2023
(PARI) my(N=70, x='x+O('x^N)); Vec((eta(-x)-1)^7) \\ Joerg Arndt, Sep 04 2023
KEYWORD
sign
EXTENSIONS
Definition and offset edited by Ilya Gutkovskiy, Feb 07 2021
STATUS
approved
Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^8 in powers of x.
(Formerly M4502 N1906)
+10
5
1, -8, 28, -56, 62, 0, -148, 328, -419, 280, 140, -728, 1232, -1336, 848, 224, -1582, 2688, -3072, 2408, -742, -1568, 3836, -5264, 5306, -3744, 924, 2576, -5686, 7792, -8092, 6272, -2751, -1848, 6008, -9296, 10556, -9800, 6692, -2240, -3206, 8168, -11524
OFFSET
8,2
REFERENCES
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
H. Gupta, On the coefficients of the powers of Dedekind's modular form, J. London Math. Soc., 39 (1964), 433-440.
FORMULA
a(n) = [x^n]( QPochhammer(-x) - 1 )^8. - G. C. Greubel, Sep 04 2023
MAPLE
g:= proc(n) option remember; `if`(n=0, 1, add(add([-d, d, -2*d, d]
[1+irem(d, 4)], d=numtheory[divisors](j))*g(n-j), j=1..n)/n)
end:
b:= proc(n, k) option remember; `if`(k=0, 1, `if`(k=1, `if`(n=0, 0, g(n)),
(q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
end:
a:= n-> b(n, 8):
seq(a(n), n=8..50); # Alois P. Heinz, Feb 07 2021
MATHEMATICA
nmax=50; CoefficientList[Series[(Product[(1 -(-x)^j), {j, nmax}] -1)^8, {x, 0, nmax}], x]//Drop[#, 8] & (* Ilya Gutkovskiy, Feb 07 2021 *)
Drop[CoefficientList[Series[(QPochhammer[-x] -1)^8, {x, 0, 102}], x], 8] (* G. C. Greubel, Sep 04 2023 *)
PROG
(Magma)
m:=102;
R<x>:=PowerSeriesRing(Integers(), m);
Coefficients(R!( ((&*[1-(-x)^j: j in [1..m+2]]) -1)^8 )); // G. C. Greubel, Sep 04 2023
(SageMath)
from sage.modular.etaproducts import qexp_eta
m=100; k=8;
def f(k, x): return (-1 + qexp_eta(QQ[['q']], m+2).subs(q=-x) )^k
def A001486_list(prec):
P.<x> = PowerSeriesRing(QQ, prec)
return P( f(k, x) ).list()
a=A001486_list(m); a[k:] # G. C. Greubel, Sep 04 2023
(PARI) my(N=55, x='x+O('x^N)); Vec((eta(-x)-1)^8) \\ Joerg Arndt, Sep 05 2023
KEYWORD
sign
EXTENSIONS
Definition and offset edited by Ilya Gutkovskiy, Feb 07 2021
STATUS
approved
Triangle T(n,k), for n >= 1, 1 <= k <= n, read by rows, giving coefficient of x^n in expansion of (Product_{j>=1} (1-(-x)^j) - 1 )^k.
+10
5
1, -1, 1, 0, -2, 1, 0, 1, -3, 1, -1, 0, 3, -4, 1, 0, -2, -1, 6, -5, 1, -1, 2, -3, -4, 10, -6, 1, 0, -2, 6, -3, -10, 15, -7, 1, 0, 2, -6, 12, 0, -20, 21, -8, 1, 0, 1, 6, -16, 19, 9, -35, 28, -9, 1, 0, 0, 0, 16, -35, 24, 28, -56, 36, -10, 1, -1, 2, -3, -6, 40, -65, 21, 62, -84, 45, -11, 1
OFFSET
1,5
COMMENTS
This is an ordinary convolution triangle. If a column k=0 starting at n=0 is added, then this is the Riordan triangle R(1, f(x)), with
f(x) = Product_{j>=1} (1 - (-x)^j) - 1, generating {0, {A121373(n)}_{n>=1}}. - Wolfdieter Lang, Feb 16 2021
LINKS
H. Gupta, On the coefficients of the powers of Dedekind's modular form, J. London Math. Soc., 39 (1964), 433-440.
FORMULA
G.f. column k: (Product_{j>=1} (1 - (-x)^j) - 1)^k, for k >= 1. See the name and a Riordan triangle comment above. - Wolfdieter Lang, Feb 16 2021
From G. C. Greubel, Sep 07 2023: (Start)
T(n, n) = 1.
T(n, n-1) = -A000027(n-1).
T(n, n-2) = A000217(n-3).
T(n, n-3) = -A000292(n-5).
Sum_{k=1..n} T(n, k) = (-1)^n * A307059(n).
Sum_{k=1..n} (-1)^k * T(n, k) = (-1)^n * A000041(n). (End)
EXAMPLE
Triangle starts:
1,
-1, 1,
0, -2, 1,
0, 1, -3, 1,
-1, 0, 3, -4, 1,
0, -2, -1, 6, -5, 1,
-1, 2, -3, -4, 10, -6, 1,
0, -2, 6, -3, -10, 15, -7, 1,
0, 2, -6, 12, 0, -20, 21, -8, 1,
0, 1, 6, -16, 19, 9, -35, 28, -9, 1,
0, 0, 0, 16, -35, 24, 28, -56, 36, -10, 1,
-1, 2, -3, -6, 40, ...
MAPLE
g:= proc(n) option remember; `if`(n=0, 1, add(add([-d, d, -2*d, d]
[1+irem(d, 4)], d=numtheory[divisors](j))*g(n-j), j=1..n)/n)
end:
T:= proc(n, k) option remember;
`if`(k=0, `if`(n=0, 1, 0), `if`(k=1, `if`(n=0, 0, g(n)),
(q-> add(T(j, q)*T(n-j, k-q), j=0..n))(iquo(k, 2))))
end:
seq(seq(T(n, k), k=1..n), n=1..12); # Alois P. Heinz, Feb 07 2021
MATHEMATICA
T[n_, k_]:= SeriesCoefficient[(-1)^n*(Product[(1-x^j), {j, n}] - 1)^k, {x, 0, n}];
Table[T[n, k], {n, 12}, {k, n}]//Flatten (* Jean-François Alcover, Dec 05 2013 *)
PROG
(PARI) T(n, k) = polcoeff((-1)^n*(Ser(prod(i=1, n, 1-x^i)-1)^k), n) \\ Ralf Stephan, Dec 08 2013
(Magma)
R<x>:=PowerSeriesRing(Integers(), 40);
T:= func< n, k | Coefficient(R!( (-1)^n*(-1 + (&*[1 - x^j: j in [1..n]]) )^k ), n) >;
[T(n, k): k in [1..n], n in [1..12]]; // G. C. Greubel, Sep 07 2023
(SageMath)
from sage.combinat.q_analogues import q_pochhammer
P.<x> = PowerSeriesRing(ZZ, 50)
def T(n, k): return P( (-1)^n*(-1 + q_pochhammer(n, x, x) )^k ).list()[n]
flatten([[T(n, k) for k in range(1, n+1)] for n in range(1, 13)]) # G. C. Greubel, Sep 07 2023
CROSSREFS
KEYWORD
sign,easy,nice,tabl
STATUS
approved
Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^20 in powers of x.
+10
4
1, -20, 190, -1140, 4825, -15124, 35320, -57760, 45220, 80560, -405954, 910460, -1289340, 852340, 1259530, -5357924, 10151510, -12048660, 5883350, 12186960, -40135713, 66244280, -69648870, 28191460, 66920755, -195366168, 300881530
OFFSET
20,2
LINKS
H. Gupta, On the coefficients of the powers of Dedekind's modular form, J. London Math. Soc., 39 (1964), 433-440.
FORMULA
a(n) = [x^n]( QPochhammer(-x) - 1 )^20. - G. C. Greubel, Sep 06 2023
MAPLE
g:= proc(n) option remember; `if`(n=0, 1, add(add([-d, d, -2*d, d]
[1+irem(d, 4)], d=numtheory[divisors](j))*g(n-j), j=1..n)/n)
end:
b:= proc(n, k) option remember; `if`(k=0, 1, `if`(k=1, `if`(n=0, 0, g(n)),
(q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
end:
a:= n-> b(n, 20):
seq(a(n), n=20..46); # Alois P. Heinz, Feb 07 2021
MATHEMATICA
nmax=46; CoefficientList[Series[(Product[(1-(-x)^j), {j, nmax}] -1)^20, {x, 0, nmax}], x]//Drop[#, 20] & (* Ilya Gutkovskiy, Feb 07 2021 *)
With[{k=20}, Drop[CoefficientList[Series[(QPochhammer[-x] -1)^k, {x, 0, 75}], x], k]] (* G. C. Greubel, Sep 06 2023 *)
PROG
(Magma)
m:=80;
R<x>:=PowerSeriesRing(Integers(), m);
Coefficients(R!( ((&*[1-(-x)^j: j in [1..m+2]]) -1)^(20) )); // G. C. Greubel, Sep 06 2023
(SageMath)
from sage.modular.etaproducts import qexp_eta
m=75; k=20;
def f(k, x): return (-1 + qexp_eta(QQ[['q']], m+2).subs(q=-x) )^k
def A047645_list(prec):
P.<x> = PowerSeriesRing(QQ, prec)
return P( f(k, x) ).list()
a=A047645_list(m); a[k:] # G. C. Greubel, Sep 06 2023
(PARI) my(N=44, x='x+O('x^N)); Vec((eta(-x)-1)^20) \\ Joerg Arndt, Sep 06 2023
KEYWORD
sign
EXTENSIONS
Definition and offset edited by Ilya Gutkovskiy, Feb 07 2021
STATUS
approved
Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^23 in powers of x.
+10
4
1, -23, 253, -1771, 8832, -33143, 95611, -209231, 317009, -181401, -686642, 2828977, -6099278, 8422623, -4906406, -10919687, 41968146, -78977952, 93297545, -40351223, -117265247, 367581446, -606562624, 631382751, -207879980, -777907725, 2132043121
OFFSET
23,2
LINKS
H. Gupta, On the coefficients of the powers of Dedekind's modular form, J. London Math. Soc., 39 (1964), 433-440.
FORMULA
a(n) = [x^n]( QPochhammer(-x) - 1 )^23. - G. C. Greubel, Sep 05 2023
MAPLE
g:= proc(n) option remember; `if`(n=0, 1, add(add([-d, d, -2*d, d]
[1+irem(d, 4)], d=numtheory[divisors](j))*g(n-j), j=1..n)/n)
end:
b:= proc(n, k) option remember; `if`(k=0, 1, `if`(k=1, `if`(n=0, 0, g(n)),
(q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
end:
a:= n-> b(n, 23):
seq(a(n), n=23..49); # Alois P. Heinz, Feb 07 2021
MATHEMATICA
nmax=49; CoefficientList[Series[(Product[(1-(-x)^j), {j, nmax}] -1)^23, {x, 0, nmax}], x]//Drop[#, 23] & (* Ilya Gutkovskiy, Feb 07 2021 *)
With[{k=23}, Drop[CoefficientList[Series[(QPochhammer[-x] -1)^k, {x, 0, 75}], x], k]] (* G. C. Greubel, Sep 05 2023 *)
PROG
(Magma)
m:=75;
R<x>:=PowerSeriesRing(Integers(), m);
Coefficients(R!( ((&*[1-(-x)^j: j in [1..m+2]]) -1)^(23) )); // G. C. Greubel, Sep 05 2023
(SageMath)
from sage.modular.etaproducts import qexp_eta
m=75; k=23;
def f(k, x): return (-1 + qexp_eta(QQ[['q']], m+2).subs(q=-x) )^k
def A047648_list(prec):
P.<x> = PowerSeriesRing(QQ, prec)
return P( f(k, x) ).list()
a=A047648_list(m); a[k:] # G. C. Greubel, Sep 05 2023
(PARI) my(N=44, x='x+O('x^N)); Vec((eta(-x)-1)^23) \\ Joerg Arndt, Sep 05 2023
KEYWORD
sign
EXTENSIONS
Definition and offset edited by Ilya Gutkovskiy, Feb 07 2021
STATUS
approved
Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^14 in powers of x.
+10
3
1, -14, 91, -364, 987, -1820, 1897, 754, -8008, 18928, -26845, 19460, 15015, -76272, 141065, -163072, 90727, 99386, -368277, 602616, -643734, 358190, 274547, -1101100, 1801086, -1982330, 1344525, 148316, -2163590, 4032756, -4938843, 4216576
OFFSET
14,2
LINKS
H. Gupta, On the coefficients of the powers of Dedekind's modular form, J. London Math. Soc., 39 (1964), 433-440.
FORMULA
a(n) = [x^n]( QPochhammer(-x) - 1 )^14. - G. C. Greubel, Sep 07 2023
MAPLE
g:= proc(n) option remember; `if`(n=0, 1, add(add([-d, d, -2*d, d]
[1+irem(d, 4)], d=numtheory[divisors](j))*g(n-j), j=1..n)/n)
end:
b:= proc(n, k) option remember; `if`(k=0, 1, `if`(k=1, `if`(n=0, 0, g(n)),
(q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
end:
a:= n-> b(n, 14):
seq(a(n), n=14..45); # Alois P. Heinz, Feb 07 2021
MATHEMATICA
nmax=45; CoefficientList[Series[(Product[(1-(-x)^j), {j, nmax}] - 1)^14, {x, 0, nmax}], x]//Drop[#, 14] & (* Ilya Gutkovskiy, Feb 07 2021 *)
With[{k=14}, Drop[CoefficientList[Series[(QPochhammer[-x] -1)^k, {x, 0, 75}], x], k]] (* G. C. Greubel, Sep 07 2023 *)
PROG
(Magma)
m:=80;
R<x>:=PowerSeriesRing(Integers(), m);
Coefficients(R!( ((&*[1-(-x)^j: j in [1..m+2]]) -1)^(14) )); // G. C. Greubel, Sep 07 2023
(SageMath)
from sage.modular.etaproducts import qexp_eta
m=75; k=14;
def f(k, x): return (-1 + qexp_eta(QQ[['q']], m+2).subs(q=-x) )^k
def A047639_list(prec):
P.<x> = PowerSeriesRing(QQ, prec)
return P( f(k, x) ).list()
a=A047639_list(m); a[k:] # G. C. Greubel, Sep 07 2023
(PARI) my(x='x+O('x^40)); Vec((eta(-x)-1)^14) \\ Joerg Arndt, Sep 07 2023
KEYWORD
sign
EXTENSIONS
Definition and offset edited by Ilya Gutkovskiy, Feb 07 2021
STATUS
approved
Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^15 in powers of x.
+10
3
1, -15, 105, -455, 1350, -2793, 3625, -765, -9840, 29120, -48657, 47370, 1680, -111060, 252555, -343526, 267540, 63210, -623510, 1216425, -1495173, 1093210, 166425, -2073645, 3963260, -4864839, 3872295, -618310, -4345470, 9477960, -12611991
OFFSET
15,2
LINKS
H. Gupta, On the coefficients of the powers of Dedekind's modular form, J. London Math. Soc., 39 (1964), 433-440.
FORMULA
a(n) = [x^n]( QPochhammer(-x) - 1 )^15. - G. C. Greubel, Sep 07 2023
MAPLE
g:= proc(n) option remember; `if`(n=0, 1, add(add([-d, d, -2*d, d]
[1+irem(d, 4)], d=numtheory[divisors](j))*g(n-j), j=1..n)/n)
end:
b:= proc(n, k) option remember; `if`(k=0, 1, `if`(k=1, `if`(n=0, 0, g(n)),
(q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
end:
a:= n-> b(n, 15):
seq(a(n), n=15..45); # Alois P. Heinz, Feb 07 2021
MATHEMATICA
nmax=45; CoefficientList[Series[(Product[(1-(-x)^j), {j, nmax}] - 1)^15, {x, 0, nmax}], x]//Drop[#, 15] & (* Ilya Gutkovskiy, Feb 07 2021 *)
With[{k=15}, Drop[CoefficientList[Series[(QPochhammer[-x] -1)^k, {x, 0, 75}], x], k]] (* G. C. Greubel, Sep 07 2023 *)
PROG
(Magma)
m:=80;
R<x>:=PowerSeriesRing(Integers(), m);
Coefficients(R!( ((&*[1-(-x)^j: j in [1..m+2]]) -1)^(15) )); // G. C. Greubel, Sep 07 2023
(SageMath)
from sage.modular.etaproducts import qexp_eta
m=75; k=15;
def f(k, x): return (-1 + qexp_eta(QQ[['q']], m+2).subs(q=-x) )^k
def A047640_list(prec):
P.<x> = PowerSeriesRing(QQ, prec)
return P( f(k, x) ).list()
a=A047640_list(m); a[k:] # G. C. Greubel, Sep 07 2023
(PARI) my(x='x+O('x^40)); Vec((eta(-x)-1)^15) \\ Joerg Arndt, Sep 07 2023
KEYWORD
sign
EXTENSIONS
Definition and offset edited by Ilya Gutkovskiy, Feb 07 2021
STATUS
approved
Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^16 in powers of x.
+10
3
1, -16, 120, -560, 1804, -4128, 6312, -3920, -10530, 42208, -82752, 99584, -39460, -141200, 422568, -673936, 660941, -144720, -938840, 2301568, -3257188, 2916592, -628040, -3492160, 8217536, -11341568, 10408280, -3885040, -7668720, 21033408
OFFSET
16,2
LINKS
H. Gupta, On the coefficients of the powers of Dedekind's modular form, J. London Math. Soc., 39 (1964), 433-440.
FORMULA
a(n) = [x^n]( QPochhammer(-x) - 1 )^16. - G. C. Greubel, Sep 07 2023
MAPLE
g:= proc(n) option remember; `if`(n=0, 1, add(add([-d, d, -2*d, d]
[1+irem(d, 4)], d=numtheory[divisors](j))*g(n-j), j=1..n)/n)
end:
b:= proc(n, k) option remember; `if`(k=0, 1, `if`(k=1, `if`(n=0, 0, g(n)),
(q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
end:
a:= n-> b(n, 16):
seq(a(n), n=16..45); # Alois P. Heinz, Feb 07 2021
MATHEMATICA
nmax=45; CoefficientList[Series[(Product[(1-(-x)^j), {j, nmax}] -1)^16, {x, 0, nmax}], x]//Drop[#, 16] & (* Ilya Gutkovskiy, Feb 07 2021 *)
With[{k=16}, Drop[CoefficientList[Series[(QPochhammer[-x] -1)^k, {x, 0, 75}], x], k]] (* G. C. Greubel, Sep 07 2023 *)
PROG
(Magma)
m:=80;
R<x>:=PowerSeriesRing(Integers(), m);
Coefficients(R!( ((&*[1-(-x)^j: j in [1..m+2]]) -1)^(16) )); // G. C. Greubel, Sep 07 2023
(SageMath)
from sage.modular.etaproducts import qexp_eta
m=75; k=16;
def f(k, x): return (-1 + qexp_eta(QQ[['q']], m+2).subs(q=-x) )^k
def A047641_list(prec):
P.<x> = PowerSeriesRing(QQ, prec)
return P( f(k, x) ).list()
a=A047641_list(m); a[k:] # G. C. Greubel, Sep 07 2023
(PARI) my(x='x+O('x^40)); Vec((eta(-x)-1)^16) \\ Joerg Arndt, Sep 07 2023
KEYWORD
sign
EXTENSIONS
Definition and offset edited by Ilya Gutkovskiy, Feb 07 2021
STATUS
approved
Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^17 in powers of x.
+10
3
1, -17, 136, -680, 2363, -5916, 10319, -9656, -8534, 57426, -133076, 190383, -134810, -140148, 657611, -1240116, 1461337, -770917, -1171504, 4061946, -6678161, 7071269, -3376863, -4939180, 15963612, -25098443, 26265408, -14513461, -10810368, 43792034
OFFSET
17,2
LINKS
H. Gupta, On the coefficients of the powers of Dedekind's modular form, J. London Math. Soc., 39 (1964), 433-440.
FORMULA
a(n) = [x^n]( QPochhammer(-x) - 1 )^17. - G. C. Greubel, Sep 07 2023
MAPLE
g:= proc(n) option remember; `if`(n=0, 1, add(add([-d, d, -2*d, d]
[1+irem(d, 4)], d=numtheory[divisors](j))*g(n-j), j=1..n)/n)
end:
b:= proc(n, k) option remember; `if`(k=0, 1, `if`(k=1, `if`(n=0, 0, g(n)),
(q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
end:
a:= n-> b(n, 17):
seq(a(n), n=17..46); # Alois P. Heinz, Feb 07 2021
MATHEMATICA
nmax=46; CoefficientList[Series[(Product[(1-(-x)^j), {j, nmax}] - 1)^17, {x, 0, nmax}], x]//Drop[#, 17] & (* Ilya Gutkovskiy, Feb 07 2021 *)
With[{k=17}, Drop[CoefficientList[Series[(QPochhammer[-x] -1)^k, {x, 0, 75}], x], k]] (* G. C. Greubel, Sep 07 2023 *)
PROG
(Magma)
m:=80;
R<x>:=PowerSeriesRing(Integers(), m);
Coefficients(R!( ((&*[1-(-x)^j: j in [1..m+2]]) -1)^(17) )); // G. C. Greubel, Sep 07 2023
(SageMath)
from sage.modular.etaproducts import qexp_eta
m=75; k=17;
def f(k, x): return (-1 + qexp_eta(QQ[['q']], m+2).subs(q=-x) )^k
def A047642_list(prec):
P.<x> = PowerSeriesRing(QQ, prec)
return P( f(k, x) ).list()
a=A047642_list(m); a[k:] # G. C. Greubel, Sep 07 2023
(PARI) my(x='x+O('x^40)); Vec((eta(-x)-1)^17) \\ Joerg Arndt, Sep 07 2023
KEYWORD
sign
EXTENSIONS
Definition and offset edited by Ilya Gutkovskiy, Feb 07 2021
STATUS
approved
Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^18 in powers of x.
+10
3
1, -18, 153, -816, 3042, -8262, 16098, -19278, -1377, 72556, -203184, 339030, -326961, -53244, 940050, -2147916, 2975391, -2293488, -911369, 6616332, -12906162, 15883884, -10936899, -4660974, 28758849, -52660134, 62518248, -44501988, -7465464, 84565242
OFFSET
18,2
LINKS
H. Gupta, On the coefficients of the powers of Dedekind's modular form, J. London Math. Soc., 39 (1964), 433-440.
FORMULA
a(n) = [x^n]( QPochhammer(-x) - 1 )^18. - G. C. Greubel, Sep 07 2023
MAPLE
g:= proc(n) option remember; `if`(n=0, 1, add(add([-d, d, -2*d, d]
[1+irem(d, 4)], d=numtheory[divisors](j))*g(n-j), j=1..n)/n)
end:
b:= proc(n, k) option remember; `if`(k=0, 1, `if`(k=1, `if`(n=0, 0, g(n)),
(q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
end:
a:= n-> b(n, 18):
seq(a(n), n=18..47); # Alois P. Heinz, Feb 07 2021
MATHEMATICA
nmax=47; CoefficientList[Series[(Product[(1-(-x)^j), {j, nmax}] -1)^18, {x, 0, nmax}], x]//Drop[#, 18] & (* Ilya Gutkovskiy, Feb 07 2021 *)
With[{k=18}, Drop[CoefficientList[Series[(QPochhammer[-x]-1)^k, {x, 0, 75}], x], k]] (* G. C. Greubel, Sep 07 2023 *)
PROG
(Magma)
m:=80;
R<x>:=PowerSeriesRing(Integers(), m);
Coefficients(R!( ((&*[1-(-x)^j: j in [1..m+2]]) -1)^(18) )); // G. C. Greubel, Sep 07 2023
(SageMath)
from sage.modular.etaproducts import qexp_eta
m=75; k=18;
def f(k, x): return (-1 + qexp_eta(QQ[['q']], m+2).subs(q=-x) )^k
def A047643_list(prec):
P.<x> = PowerSeriesRing(QQ, prec)
return P( f(k, x) ).list()
a=A047643_list(m); a[k:] # G. C. Greubel, Sep 07 2023
(PARI) my(x='x+O('x^35)); Vec((eta(-x)-1)^18) \\ Joerg Arndt, Sep 07 2023
KEYWORD
sign
EXTENSIONS
Definition and offset edited by Ilya Gutkovskiy, Feb 07 2021
STATUS
approved

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