a(n)=(2^n-1)*2^(n(n-1)/2)/(2^(n-1)).

A127850

a(n)=(2^n-1)*2^(n(n-1)/2)/(2^(n-1)).

Terms

    a(0) =0a(1) =1a(2) =3a(3) =14a(4) =120a(5) =1984a(6) =64512a(7) =4161536a(8) =534773760a(9) =137170518016

External references