a(n) = (8*n+1)*(8*n+3)*(8*n+5)*(8*n+7).

Terms

a(0) =105a(1) =19305a(2) =156009a(3) =606825a(4) =1666665a(5) =3728745a(6) =7284585a(7) =12924009a(8) =21335145a(9) =33304425a(10) =49716585a(11) =71554665a(12) =99900009a(13) =135932265a(14) =180929385a(15) =236267625a(16) =303421545a(17) =383964009a(18) =479566185a(19) =591997545a(20) =723125865a(21) =874917225a(22) =1049436009a(23) =1248844905a(24) =1475404905