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 A385103 #30 Jun 26 2025 23:14:19 %S A385103 0,1,1,0,2,2,1,0,1,4,2,1,4,3,2,0,1,2,2,1,3,3,1,1,2,6,1,1,3,6,1,0,2,2, %T A385103 5,1,4,3,3,1,1,4,3,1,2,3,1,1,1,4,1,2,4,2,3,2,3,5,2,3,4,3,1,0,5,5,2,1, %U A385103 2,8,3,1,3,8,3,1,3,4,2,1,1,3,2,3,5,4,3,1,4,6,5,2,3,3,2,1,5,2,3,1 %N A385103 Number of values of s, 0 < s < n, such that -(s^s) == s (mod n). %p A385103 a:= n-> add(`if`(s&^s+s mod n=0, 1, 0), s=1..n-1): %p A385103 seq(a(n), n=1..100); # _Alois P. Heinz_, Jun 20 2025 %o A385103 (PARI) a(n) = sum(s=1, n-1, -Mod(s, n)^s == s); \\ _Michel Marcus_, Jun 19 2025 %Y A385103 Cf. A065295, A151821, A373901, A382752, A384781, A384854. %K A385103 nonn %O A385103 1,5 %A A385103 _Juri-Stepan Gerasimov_, Jun 17 2025