a(n) = phi(8^n+1), where phi is Euler's totient function (A000010).

A366658

a(n) = phi(8^n+1), where phi is Euler's totient function (A000010).

Terms

    a(0) =1a(1) =6a(2) =48a(3) =324a(4) =3840a(5) =19800a(6) =186624a(7) =1365336a(8) =16515072a(9) =84768120a(10) =760320000a(11) =5632621632a(12) =64258375680a(13) =366369658200

External references