a(n) = Sum_{k=0..n} binomial(n,k) * binomial(3*n+3*k,k).
A388726
a(n) = Sum_{k=0..n} binomial(n,k) * binomial(3*n+3*k,k).
Terms
- a(0) =1a(1) =7a(2) =85a(3) =1168a(4) =16925a(5) =252687a(6) =3845650a(7) =59315361a(8) =923951637a(9) =14501802175a(10) =228982156315
External references
- oeis: A388726