a(0)=1, a(1)=3, a(n) = sum_{k=0}^{k=n-1} 3^k a(k).
A015487
a(0)=1, a(1)=3, a(n) = sum_{k=0}^{k=n-1} 3^k a(k).
Terms
- a(0) =1a(1) =3a(2) =10a(3) =100a(4) =2800a(5) =229600a(6) =56022400a(7) =40896352000
External references
- oeis: A015487
A015487
a(0)=1, a(1)=3, a(n) = sum_{k=0}^{k=n-1} 3^k a(k).