a(n) = Sum_{k=0..n} binomial(n,k) * binomial(n+3*k,n).
A378402
a(n) = Sum_{k=0..n} binomial(n,k) * binomial(n+3*k,n).
Terms
- a(0) =1a(1) =5a(2) =49a(3) =533a(4) =6081a(5) =71365a(6) =853105a(7) =10331221a(8) =126321409a(9) =1556044805a(10) =19280812849a(11) =240054516245
External references
- oeis: A378402