OFFSET
0,3
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..50
FORMULA
a(n) ~ c * 2^(n*(n+1)/2), where c = A048651 = 0.2887880950866... . - Vaclav Kotesovec, Nov 21 2015
MATHEMATICA
Table[Sum[(-1)^(n+k) Binomial[n, k] QFactorial[k, 2], {k, 0, n}], {n, 0, 15}] (* Vladimir Reshetnikov, Nov 20 2015 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Vladeta Jovovic, Dec 05 2008
STATUS
approved