a(n) = phi(n^8) = n^7*phi(n).

Terms

a(0) =1a(1) =128a(2) =4374a(3) =32768a(4) =312500a(5) =559872a(6) =4941258a(7) =8388608a(8) =28697814a(9) =40000000a(10) =194871710a(11) =143327232a(12) =752982204a(13) =632481024a(14) =1366875000a(15) =2147483648a(16) =6565418768a(17) =3673320192a(18) =16089691302a(19) =10240000000a(20) =21613062492a(21) =24943578880a(22) =74906159834a(23) =36691771392a(24) =122070312500