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

Terms

a(0) =1a(1) =64a(2) =1458a(3) =8192a(4) =62500a(5) =93312a(6) =705894a(7) =1048576a(8) =3188646a(9) =4000000a(10) =17715610a(11) =11943936a(12) =57921708a(13) =45177216a(14) =91125000a(15) =134217728a(16) =386201104a(17) =204073344a(18) =846825858a(19) =512000000a(20) =1029193452a(21) =1133799040a(22) =3256789558a(23) =1528823808a(24) =4882812500a(25) =3706989312a(26) =6973568802a(27) =5782683648a(28) =16655052988