OFFSET
0,3
COMMENTS
Compare to the identity: 1/(1-x) = Sum_{n>=0} n^n * exp(-n*x) * x^n/n!.
Compare to the o.g.f. of A007820:
Sum_{n>=0} S2(2*n,n)*x^n = Sum_{n>=0} (n^2)^n * exp(-n^2*x) * x^n/n!.
EXAMPLE
E.g.f.: 1/(1-x) = 1 + 1*exp(-x)*x + 4*exp(-2^2*x)*x^2/2! + 51*exp(-3^2*x)*x^3/3! + 1480*exp(-4^2*x)*x^4/4! + 79765*exp(-5^2*x)*x^5/5! + 7010496*exp(-6^2*x)*x^6/6!+...
PROG
(PARI) {a(n)=n!*polcoeff(1/(1-x+x*O(x^n))-sum(k=0, n-1, a(k)*x^k/k!*exp(-k^2*x+x*O(x^n))), n)}
for(n=0, 16, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Dec 11 2012
STATUS
approved