a(n) = (4*n+1)*(4*n+3)*(4*n+5)*(4*n+7).

Terms

a(0) =105a(1) =3465a(2) =19305a(3) =62985a(4) =156009a(5) =326025a(6) =606825a(7) =1038345a(8) =1666665a(9) =2544009a(10) =3728745a(11) =5285385a(12) =7284585a(13) =9803145a(14) =12924009a(15) =16736265a(16) =21335145a(17) =26822025a(18) =33304425a(19) =40896009a(20) =49716585a(21) =59892105a(22) =71554665a(23) =84842505a(24) =99900009a(25) =116877705a(26) =135932265a(27) =157226505a(28) =180929385