a(n) = binomial(n+5, n)*binomial(n+10, n).

Terms

a(0) =1a(1) =66a(2) =1386a(3) =16016a(4) =126126a(5) =756756a(6) =3699696a(7) =15402816a(8) =56316546a(9) =184940756a(10) =554822268a(11) =1540663488a(12) =4001445448a(13) =9802357488a(14) =22805484768a(15) =50678855040a(16) =108088495515a(17) =222161129190a(18) =441579528390a(19) =851355545040