a(n) = n^6 - n^4.

Terms

a(0) =0a(1) =0a(2) =48a(3) =648a(4) =3840a(5) =15000a(6) =45360a(7) =115248a(8) =258048a(9) =524880a(10) =990000a(11) =1756920a(12) =2965248a(13) =4798248a(14) =7491120a(15) =11340000a(16) =16711680a(17) =24054048a(18) =33907248a(19) =46915560a(20) =63840000a(21) =85571640a(22) =113145648a(23) =147756048a(24) =190771200a(25) =243750000a(26) =308458800a(27) =386889048a(28) =481275648