a(0)=1, a(1)=2, a(n) = sum_{k=0}^{k=n-1} 2^k a(k).

A015486

a(0)=1, a(1)=2, a(n) = sum_{k=0}^{k=n-1} 2^k a(k).

Terms

    a(0) =1a(1) =2a(2) =5a(3) =25a(4) =225a(5) =3825a(6) =126225a(7) =8204625a(8) =1058396625a(9) =272007932625

External references