a(n) = binomial(n+4,4)*binomial(n+6,4).

Terms

a(0) =15a(1) =175a(2) =1050a(3) =4410a(4) =14700a(5) =41580a(6) =103950a(7) =235950a(8) =495495a(9) =975975a(10) =1821820a(11) =3248700a(12) =5569200a(13) =9224880a(14) =14825700a(15) =23197860a(16) =35441175a(17) =52997175a(18) =77729190a(19) =112015750a(20) =158858700a(21) =222007500a(22) =306101250a(23) =416830050a(24) =561117375a(25) =747325215a(26) =985483800a(27) =1287547800