a(n) = (2*n+n^2)*(binomial(2*n,n))/2.

Terms

a(0) =0a(1) =3a(2) =24a(3) =150a(4) =840a(5) =4410a(6) =22176a(7) =108108a(8) =514800a(9) =2406690a(10) =11085360a(11) =50438388a(12) =227149104a(13) =1014058500a(14) =4493059200a(15) =19777483800a(16) =86555576160a(17) =376877404530