a(n) = Sum_{k=0..n} binomial(n,k) * binomial(n+1,k+1) * 3^k.
A098663
a(n) = Sum_{k=0..n} binomial(n,k) * binomial(n+1,k+1) * 3^k.
Terms
- a(0) =1a(1) =5a(2) =30a(3) =193a(4) =1286a(5) =8754a(6) =60460a(7) =421985a(8) =2968902a(9) =21019510a(10) =149572292a(11) =1068795930a(12) =7664092060a(13) =55121602436a(14) =397464604440
External references
- oeis: A098663