a(n) = 4*36^n*Gamma(n+3/2)/(sqrt(Pi)*(n+2)!).

A260655

a(n) = 4*36^n*Gamma(n+3/2)/(sqrt(Pi)*(n+2)!).

Terms

    a(0) =1a(1) =18a(2) =405a(3) =10206a(4) =275562a(5) =7794468a(6) =227988189a(7) =6839645670a(8) =209293157502

External references