OFFSET
0,4
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..50
FORMULA
E.g.f.: exp(-x^2/2)*Sum_{n>=0} 2^binomial(n,2)*x^n/n!.
a(n) = n!*Sum_{q=0..floor(n/2)} ((-1)^q/(2^q*q!))*(2^C(n-2*q,2)/(n-2*q)!). - Marko Riedel, Apr 05 2022
MAPLE
A093352 := n -> n!*add((-1)^q/2^q/q!*2^binomial(n-2*q, 2)/(n-2*q)!, q=0..floor(n/2)); # Marko Riedel, Apr 05 2022
MATHEMATICA
nn = 15; g = Sum[2^Binomial[n, 2] x^n/n!, {n, 0, nn}];
Range[0, nn]! CoefficientList[Series[g/Exp[x^2/2], {x, 0, nn}], x] (* Geoffrey Critzer, Aug 27 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Goran Kilibarda, Vladeta Jovovic, Apr 26 2004
STATUS
approved