G.f.: Sum_{n>=0} (3*(1+x)^n - 1)^n / 3^(n+1).

A317798

G.f.: Sum_{n>=0} (3*(1+x)^n - 1)^n / 3^(n+1).

Terms

    a(0) =1a(1) =15a(2) =786a(3) =69261a(4) =8554530a(5) =1359020643a(6) =263929299177

External references