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 A056031 #18 Apr 10 2025 08:37:31 %S A056031 1,28,42,63,118,130,170,177,195,255,263,266,274,334,352,359,399,411, %T A056031 466,487,501,528,530,557,571,592,647,659,699,706,724,784,792,795,803, %U A056031 863,881,888,928,940,995,1016,1030,1057,1059,1086,1100,1121,1176,1188 %N A056031 Numbers k such that k^22 == 1 (mod 23^2). %H A056031 Amiram Eldar, <a href="/A056031/b056031.txt">Table of n, a(n) for n = 1..10000</a> %H A056031 <a href="/index/Rec#order_23">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,-1). %F A056031 From _Mike Sheppard_, Feb 20 2025 : (Start) %F A056031 a(n) = a(n-1) + a(n-22) - a(n-23). %F A056031 a(n) = a(n-22) + 23^2. %F A056031 a(n) ~ (23^2/22)*n. (End) %t A056031 x=23; Select[ Range[ 2000 ], PowerMod[ #, x-1, x^2 ]==1& ] %Y A056031 Cf. A056021, A056022, A056024, A056025, A056026, A056027, A056028, A056034, A056035. %Y A056031 Cf. A381319 (general case mod n^2). %K A056031 nonn %O A056031 1,2 %A A056031 _Robert G. Wilson v_, Jun 08 2000