a(n) = binomial(2^n + 1, n).A136505a(n) = binomial(2^n + 1, n).Terms a(0) =1a(1) =3a(2) =10a(3) =84a(4) =2380a(5) =237336a(6) =82598880a(7) =99949406400External referencesoeis: A136505