A366685 a(n) = phi(11^n-1), where phi is Euler's totient function (A000010).

4, 32, 432, 3840, 64400, 373248, 7613424, 56217600, 765889344, 6913984000, 114117380608, 599824465920, 13796450740800, 98909341090560, 1356399209088000, 11341872916070400, 202178811399717504, 1171410130065973248, 24463636179365818512, 176391086415667200000

Offset: 1

Author

Sean A. Irvine, Oct 16 2023

Keywords

• nonn

Links

• Max Alekseyev, Table of n, a(n) for n = 1..316

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), this sequence (k=11), A366711 (k=12).

Cf. A000010, A024127, A366681, A366682, A366683, A366684.

Programs

Mathematica

EulerPhi[11^Range[30] - 1]

PARI

{a(n) = eulerphi(11^n-1)}