a(n) = (n+1)*(n+2)*(n+3)*(13*n^3 + 69*n^2 + 113*n + 60)/360.

Terms

a(0) =1a(1) =17a(2) =111a(3) =457a(4) =1428a(5) =3710a(6) =8442a(7) =17382a(8) =33099a(9) =59191a(10) =100529a(11) =163527a(12) =256438a(13) =389676a(14) =576164a(15) =831708a(16) =1175397a(17) =1630029a(18) =2222563a(19) =2984597a(20) =3952872a(21) =5169802a(22) =6684030a(23) =8551010a(24) =10833615a(25) =13602771a(26) =16938117a(27) =20928691a(28) =25673642a(29) =31282968