a(n) = Sum_{j = 0..3*n} binomial(n+j-1,j)*2^j.

A333562

a(n) = Sum_{j = 0..3*n} binomial(n+j-1,j)*2^j.

Terms

    a(0) =1a(1) =15a(2) =769a(3) =47103a(4) =3080193a(5) =208470015a(6) =14413725697

External references