OFFSET
0,4
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..50
FORMULA
E.g.f.: exp(x^2)*(Sum_{n >= 0} 3^(n*(n-1)/2)*(x/exp(2*x))^n/n!).
MATHEMATICA
m = 14;
egf = Exp[x^2]*Sum[3^(n (n - 1)/2)*(x/Exp[2 x])^n/n!, {n, 0, m}];
a[n_] := SeriesCoefficient[egf, {x, 0, n}]*n!;
Table[a[n], {n, 0, m}] (* Jean-François Alcover, Feb 23 2019 *)
PROG
(PARI) seq(n)={my(A=x/exp(2*x+O(x^n))); Vec(serlaplace(exp(x^2 + O(x*x^n)) * sum(k=0, n, 3^binomial(k, 2)*A^k/k!)))} \\ Andrew Howroyd, Sep 09 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Goran Kilibarda, Zoran Maksimovic, Vladeta Jovovic, Jan 02 2005
EXTENSIONS
Terms a(13) and beyond from Andrew Howroyd, Sep 09 2018
STATUS
approved