OFFSET
0,3
LINKS
Robert Israel, Table of n, a(n) for n = 0..449
FORMULA
E.g.f.: Product_{k>0} exp(x^(3*k-1)) / exp(x^(3*k)).
(n+3)*(n+2)*(n+1)*n*a(n)+(2*n+1)*(n+3)*(n+2)*a(n+1)+(3*n+4)*(n+3)*a(n+2)+2*(n+3)*a(n+3)+a(n+4)=0. - Robert Israel, Oct 27 2019
MAPLE
rec:= (n+3)*(n+2)*(n+1)*n*b(n)+(2*n+1)*(n+3)*(n+2)*b(n+1)+(3*n+4)*(n+3)*b(n+2)+2*(n+3)*b(n+3)+b(n+4)=0:
f:= gfun:-rectoproc({rec, b(0)=1, b(1)=0, b(2)=2, b(3)=-6}, b(n), remember):
map(f, [$0..30]); # Robert Israel, Oct 27 2019
MATHEMATICA
CoefficientList[Series[E^(x^2/(1 + x + x^2)), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Oct 13 2017 *)
PROG
(PARI) N=66; x='x+O('x^N); Vec(serlaplace(exp(x^2/(1+x+x^2))))
(PARI) N=66; x='x+O('x^N); Vec(serlaplace(prod(k=1, N, exp(x^(3*k-1)-x^(3*k)))))
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Oct 12 2017
STATUS
approved