a(n) = (n+1)*(n+2)*(n+3)*(n+4)*(7*n^2 + 20*n + 15)/360.

Terms

a(0) =1a(1) =14a(2) =83a(3) =322a(4) =966a(5) =2436a(6) =5418a(7) =10956a(8) =20559a(9) =36322a(10) =61061a(11) =98462a(12) =153244a(13) =231336a(14) =340068a(15) =488376a(16) =687021a(17) =948822a(18) =1288903a(19) =1724954a(20) =2277506a(21) =2970220a(22) =3830190a(23) =4888260a(24) =6179355a(25) =7742826a(26) =9622809a(27) =11868598a(28) =14535032a(29) =17682896