(n+n^2+n^3)*(binomial(2*n,n)).

Terms

a(0) =0a(1) =6a(2) =84a(3) =780a(4) =5880a(5) =39060a(6) =238392a(7) =1369368a(8) =7516080a(9) =39819780a(10) =205079160a(11) =1032047016a(12) =5094629904a(13) =24743027400a(14) =118504436400a(15) =560749834800