A366579 a(n) = phi(3^n+1), where phi is Euler's totient function (A000010).

1, 2, 4, 12, 40, 120, 288, 1092, 3072, 7776, 23600, 87120, 259200, 797160, 1847104, 5832000, 21523360, 63672480, 152845056, 580921200, 1700870400, 4368821184, 12550120000, 47071589412, 130459631616, 413939700000, 997562438080, 3012122557440, 11159367815680

Offset: 0

Author

Sean A. Irvine, Oct 13 2023

Keywords

• nonn

Links

• Max Alekseyev, Table of n, a(n) for n = 0..691

Crossrefs

Cf. A000010, A002592, A034472, A053285, A057935, A057941, A074476, A274909, A295500, A366577, A366578, A366580.

Programs

Mathematica

EulerPhi[3^Range[0,30]+1] (* Paolo Xausa, Oct 15 2023 *)

PARI

{a(n) = eulerphi(3^n+1)}

Formula

a(n) = phi(3^n+1) = A000010(A034472(n)).