a(n) = n^8 - n^7.

Terms

a(0) =0a(1) =0a(2) =128a(3) =4374a(4) =49152a(5) =312500a(6) =1399680a(7) =4941258a(8) =14680064a(9) =38263752a(10) =90000000a(11) =194871710a(12) =394149888a(13) =752982204a(14) =1370375552a(15) =2392031250a(16) =4026531840a(17) =6565418768a(18) =10407740544a(19) =16089691302a(20) =24320000000a(21) =36021770820a(22) =52381515648a(23) =74906159834a(24) =105488842752a(25) =146484375000