This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A366685 #9 Jan 04 2024 19:14:41
%S A366685 4,32,432,3840,64400,373248,7613424,56217600,765889344,6913984000,
%T A366685 114117380608,599824465920,13796450740800,98909341090560,
%U A366685 1356399209088000,11341872916070400,202178811399717504,1171410130065973248,24463636179365818512,176391086415667200000
%N A366685 a(n) = phi(11^n-1), where phi is Euler's totient function (A000010).
%H A366685 Max Alekseyev, <a href="/A366685/b366685.txt">Table of n, a(n) for n = 1..316</a>
%t A366685 EulerPhi[11^Range[30] - 1]
%o A366685 (PARI) {a(n) = eulerphi(11^n-1)}
%Y A366685 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).
%Y A366685 Cf. A000010, A024127, A366681, A366682, A366683, A366684.
%K A366685 nonn
%O A366685 1,1
%A A366685 _Sean A. Irvine_, Oct 16 2023