a(n) = (n+1)*(n+2)^2*(n+3)^2*(n+4)*(n^2 + 5*n + 5)/720.

Terms

a(0) =1a(1) =22a(2) =190a(3) =1015a(4) =4018a(5) =12936a(6) =35784a(7) =88110a(8) =197835a(9) =412126a(10) =806806a(11) =1498861a(12) =2662660a(13) =4550560a(14) =7518624a(15) =12058236a(16) =18834453a(17) =28731990a(18) =42909790a(19) =62865187a(20) =90508726a(21) =128250760a(22) =179101000a(23) =246782250a(24) =335859615a(25) =451886526a(26) =601568982