OFFSET
0,3
COMMENTS
Compare e.g.f. to the o.g.f. of A007820: Sum_{n>=0} (n^2)^n * exp(-n^2*x) * x^n/n!.
EXAMPLE
E.g.f.: A(x) = 1 + x + 16*x^2/2! + 732*x^3/3! + 67072*x^4/4! + 10356120*x^5/5! +...
PROG
(PARI) {a(n)=polcoeff(serlaplace(sum(k=0, n, (k^2*x)^k/k!*cosh(-k^2*x +x*O(x^n)))), n)}
for(n=0, 20, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Oct 27 2012
STATUS
approved