a(n) = Sum_{k=0..n} 3^k * binomial(n+k-1,k).
A383888
a(n) = Sum_{k=0..n} 3^k * binomial(n+k-1,k).
Terms
- a(0) =1a(1) =4a(2) =34a(3) =334a(4) =3478a(5) =37384a(6) =409960a(7) =4558306a(8) =51199558a(9) =579554056a(10) =6600532684a(11) =75546800476a(12) =868224027916
External references
- oeis: A383888