For n > 0: a(n) = Sum_{r=0..2^(n-1)-1} binomial(2^n, 2r+1)*3^r.

A084595

For n > 0: a(n) = Sum_{r=0..2^(n-1)-1} binomial(2^n, 2r+1)*3^r.

Terms

    a(0) =1a(1) =2a(2) =16a(3) =896a(4) =2781184

External references