OFFSET
0,3
COMMENTS
REFERENCES
E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 93 (22nd row of the table).
LINKS
Bruno Berselli, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
G.f.: x*(1 + 21*x)/(1 - x)^4.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) with n>3, a(0)=0, a(1)=1, a(2)=25, a(3)=94.
a(n) = Sum_{i=0..n-1} (n-i)*(22*i+1) for n>0.
MATHEMATICA
Table[n (n + 1) (22 n - 19)/6, {n, 0, 40}]
PROG
(PARI) vector(40, n, n--; n*(n+1)*(22*n-19)/6)
(Sage) [n*(n+1)*(22*n-19)/6 for n in (0..40)]
(Magma) [n*(n+1)*(22*n-19)/6: n in [0..40]];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Bruno Berselli, Apr 09 2015
STATUS
approved