OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..70
FORMULA
a(n) = 2^C(n+1,2)*Sum_{k=0..floor(n/2)} C(n,2k)*2^(n-k).
a(n) = 4^n*A166232(n).
MATHEMATICA
Table[2^(Binomial[n + 1, 2])*Sum[Binomial[n, 2 k]*2^(n - k), {k, 0, Floor[n/2]}], {n, 0, 25}] (* G. C. Greubel, May 07 2016 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Oct 09 2009
STATUS
approved