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 A122904 #11 Nov 11 2024 05:25:56 %S A122904 5,7,8,9,11,13,15,16,17,19,20,21,23,24,25,27,28,29,31,32,33,35,36,37, %T A122904 39,40,41,43,44,45,47,48,49,51,52,53,55,56,57,59,60,61,63,64,65,67,68, %U A122904 69,71,72,73,75,76,77,79,80,81,83,84,85,87,88,89,91,92,93,95,96,97,99,100 %N A122904 Numbers m such that in Z/mZ the number of squares is strictly less than the number of invertible elements. %C A122904 Numbers m such that A000224(m) < A000010(m). %H A122904 Ivan Neretin, <a href="/A122904/b122904.txt">Table of n, a(n) for n = 1..10000</a> %t A122904 Select[Range@100, Length@Union@Mod[Range[#]^2, #] < EulerPhi[#] &] (* _Ivan Neretin_, Dec 14 2016 *) %t A122904 f1[p_, e_] := Floor[p^(e+1)/(2p + 2)] + 1; f1[2, e_] := Floor[2^e/6] + 2; f[p_, e_] := f1[p, e]/((p-1) * p^(e-1)); q[1] = False; q[k_] := Times @@ f @@@ FactorInteger[k] < 1; Select[Range[100], q] (* _Amiram Eldar_, Nov 11 2024 *) %Y A122904 Cf. A000010, A000224, A122903, A122905, A122906, A122907. %K A122904 nonn %O A122904 1,1 %A A122904 _Max Alekseyev_, Sep 18 2006