a(n) = n*(105*n^3 - 210*n^2 + 147*n - 34).

Terms

a(0) =0a(1) =8a(2) =520a(3) =4056a(4) =15656a(5) =42880a(6) =95808a(7) =187040a(8) =331696a(9) =547416a(10) =854360a(11) =1275208a(12) =1835160a(13) =2561936a(14) =3485776a(15) =4639440a(16) =6058208a(17) =7779880a(18) =9844776a(19) =12295736a(20) =15178120a(21) =18539808a(22) =22431200a(23) =26905216a(24) =32017296a(25) =37825400a(26) =44390008a(27) =51774120a(28) =60043256a(29) =69265456