OFFSET
0,3
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
D. Callan, T. Mansour, Enumeration of small Wilf Classes avoiding 1342 and two other 4-letter patterns, arXiv:1708.00832 [math.CO] (2017). Table 1 No 106.
Index entries for linear recurrences with constant coefficients, signature (9,-31,52,-45,19,-3).
FORMULA
O.g.f.: (1 - 2*x)*(1 - 6*x + 12*x^2 - 9*x^3 + 4*x^4)/((1 - x)^3*(1 - 3*x)*(1 - 3*x + x^2)).
a(n) = 9*a(n-1) - 31*a(n-2) + 52*a(n-3) - 45*a(n-4) + 19*a(n-5) - 3*a(n-6) for n>5. - Colin Barker, Nov 07 2017
MAPLE
p := (1-2*x)*(1-6*x+12*x^2-9*x^3+4*x^4) :
q := (1-x)^3*(1-3*x)*(1-3*x+x^2) :
taylor(p/q, x=0, 40) :
gfun[seriestolist](%) ;
PROG
(PARI) Vec((1 - 2*x)*(1 - 6*x + 12*x^2 - 9*x^3 + 4*x^4) / ((1 - x)^3*(1 - 3*x)*(1 - 3*x + x^2)) + O(x^40)) \\ Colin Barker, Nov 07 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. J. Mathar, Nov 07 2017
STATUS
approved