a(n) = gcd(n^n, phi(n^n)).

Terms

a(0) =1a(1) =2a(2) =9a(3) =128a(4) =625a(5) =15552a(6) =117649a(7) =8388608a(8) =129140163a(9) =2000000000a(10) =25937424601