Generalized Euler phi function (for p=5).

Terms

a(0) =1a(1) =16a(2) =96a(3) =256a(4) =2500a(5) =9216a(6) =62496a(7) =147456a(8) =1499904a(9) =6250000a(10) =39037504a(11) =84934656a(12) =971882496a(13) =3905750016a(14) =23437500000a(15) =57415827456a(16) =610351562496