OFFSET
1,2
COMMENTS
A193467 is defined by the e.g.f.: Sum_{n>=0} x^n * exp(n*(n+1)/2*x).
FORMULA
O.g.f.: x * Sum_{k>=0} k! * x^k / (1 - binomial(k+2,2)*x)^(k+1). - Ilya Gutkovskiy, Jul 16 2019
PROG
(PARI) {a(n)=local(Egf); Egf=sum(m=0, n, x^m*exp(m*(m+1)/2*x+x*O(x^n))); if(n<1, 0, (n-1)!*polcoeff(Egf, n))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jul 27 2011
STATUS
approved