a(n) = Sum_{k=0..n} binomial(n+k-1,k) * binomial(n+3*k-1,n-k).
A378567
a(n) = Sum_{k=0..n} binomial(n+k-1,k) * binomial(n+3*k-1,n-k).
Terms
- a(0) =1a(1) =1a(2) =11a(3) =88a(4) =715a(5) =5951a(6) =50288a(7) =429696a(8) =3702987a(9) =32125390a(10) =280211701a(11) =2454992618a(12) =21588647392a(13) =190444368401
External references
- oeis: A378567