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 A329222 #16 Sep 08 2022 08:46:24 %S A329222 1,2,6,13,14,174,854,2694,78126,103973,106694,121974,420209,487374, %T A329222 1299374,2174654,3895094,4151454,5842214,5951129,6508334,10637054, %U A329222 20117894,24482957,31999694,32282053,32620202,32872454,34258454,52657397,56114618,57679082,65538437,70782774,71899526 %N A329222 Numbers m that divide 5^(m + 1) + 1. %C A329222 Conjecture: For k > 1, k^(m + 1) == -1 (mod m) has an infinite number of positive solutions. %t A329222 Select[Range[719*10^5],PowerMod[5,#+1,#]==#-1&] (* _Harvey P. Dale_, Jul 03 2020 *) %o A329222 (Magma) [n + 1: n in [0..2000000] | Modexp(5, n + 2, n + 1) eq n]; %o A329222 (PARI) isok(m) = Mod(5, m)^(m+1) == -1; \\ _Jinyuan Wang_, Nov 16 2019 %Y A329222 Cf. A055685. %Y A329222 Solutions to k^(m + 1) == -1 (mod m): A296369 (k=2), A328230 (k=3), A329168 (k=4), this sequence (k=5), A329226 (k=6). %K A329222 nonn %O A329222 1,2 %A A329222 _Juri-Stepan Gerasimov_, Nov 08 2019