a(n) = (2n+1)*(2n+2)*(2n+6)*(2n+7).

Terms

a(0) =84a(1) =864a(2) =3300a(3) =8736a(4) =18900a(5) =35904a(6) =62244a(7) =100800a(8) =154836a(9) =228000a(10) =324324a(11) =448224a(12) =604500a(13) =798336a(14) =1035300a(15) =1321344a(16) =1662804a(17) =2066400a(18) =2539236a(19) =3088800a(20) =3722964a(21) =4449984a(22) =5278500a(23) =6217536a(24) =7276500a(25) =8465184a(26) =9793764a(27) =11272800a(28) =12913236a(29) =14726400