a(n) = n^8-n.

Terms

a(0) =0a(1) =0a(2) =254a(3) =6558a(4) =65532a(5) =390620a(6) =1679610a(7) =5764794a(8) =16777208a(9) =43046712a(10) =99999990a(11) =214358870a(12) =429981684a(13) =815730708a(14) =1475789042a(15) =2562890610a(16) =4294967280a(17) =6975757424a(18) =11019960558a(19) =16983563022a(20) =25599999980a(21) =37822859340a(22) =54875873514a(23) =78310985258a(24) =110075314152