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 A381122 #13 Feb 15 2025 12:28:19 %S A381122 0,1,4,8,12,20,24,28,32,36,44,56,60,72,80,84,92,104,116,120,132,140, %T A381122 144,156,164,168,176,180,192,200,204,212,216,224,252,260,272,276,296, %U A381122 300,312,324,332,344,356,360,380,384,392,396,420,444,452,456,464,476,480,500,512,524,536,540,552,560 %N A381122 Numbers k such that k^(k+1) == k (mod k+2). %C A381122 Numbers k such that (-2)^(k+1) == k (mod k+2). %C A381122 Odd terms are k-2 for k >= 3 in A115976. %C A381122 Even terms are divisible by 4. %H A381122 Robert Israel, <a href="/A381122/b381122.txt">Table of n, a(n) for n = 1..10000</a> %e A381122 a(5) = 12 is a term because 12^13 == 12 (mod 14). %p A381122 select(k -> (-2) &^(k+1) mod (k+2) = k, [$1..1000]); %t A381122 Select[Range[0,560],PowerMod[#,#+1,#+2]==#&] (* _James C. McMahon_, Feb 15 2025 *) %Y A381122 Cf. A064935, A115976. %K A381122 nonn %O A381122 1,3 %A A381122 _Robert Israel_, Feb 14 2025