a(n) = Sum_{k=0..n} binomial(4*n+k+1,n-k).
A390333
a(n) = Sum_{k=0..n} binomial(4*n+k+1,n-k).
Terms
- a(0) =1a(1) =6a(2) =47a(3) =393a(4) =3388a(5) =29737a(6) =264143a(7) =2366479a(8) =21339187a(9) =193401090a(10) =1760033001a(11) =16071380452a(12) =147170921305
External references
- oeis: A390333