a(n) = 5*binomial(4*n+5,n)/(4*n+5).

Terms

a(0) =1a(1) =5a(2) =30a(3) =200a(4) =1425a(5) =10626a(6) =81900a(7) =647280a(8) =5217300a(9) =42724825a(10) =354465254a(11) =2973052680a(12) =25168220350a(13) =214762810500