A366711 a(n) = phi(12^n-1), where phi is Euler's totient function (A000010).

10, 120, 1560, 13440, 226200, 2021760, 32518360, 274391040, 4534807680, 51953616000, 646094232960, 4662793175040, 97266341877120, 1070382142166400, 13666309113600000, 109897747141754880, 2016918439151095000, 17518491733377024000, 290436363064202660760

Offset: 1

Author

Sean A. Irvine, Oct 17 2023

Keywords

• nonn

Links

• Max Alekseyev, Table of n, a(n) for n = 1..310

Crossrefs

phi(k^n-1): A053287 (k=2), A295500 (k=3), A295501 (k=4), A295502 (k=5), A366623 (k=6), A366635 (k=7), A366654 (k=8), A366663 (k=9), A295503 (k=10), A366685 (k=11), this sequence (k=12).

Cf. A000010, A024140, A366707, A366708, A366709, A366710, A366717, A366718.

Programs

Mathematica

EulerPhi[12^Range[30] - 1]

PARI

{a(n) = eulerphi(12^n-1)}