G.f.: Sum_{n>=0} ( (1+x)^n - (1-x)^n )^n / 2^n.

A302108

G.f.: Sum_{n>=0} ( (1+x)^n - (1-x)^n )^n / 2^n.

Terms

    a(0) =1a(1) =1a(2) =4a(3) =27a(4) =256a(5) =3152a(6) =47680a(7) =854802a(8) =17711872a(9) =416372620a(10) =10947581056a(11) =318304921165

External references