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 A374912 #19 Jul 24 2024 09:47:48 %S A374912 3,7,19,31,79,139,199,211,271,307,331,367,379,439,499,547,607,619,691, %T A374912 727,811,967,1171,1279,1399,1459,1531,1627,1759,1867,2011,2131,2179, %U A374912 2311,2467,2539,2551,2707,2719,2791,2851,3019,3067,3187,3319,3331,3391,3499,3607,3739,3967 %N A374912 Primes p such that (p - 1)^p == p (mod 2*p - 1). %H A374912 Paolo Xausa, <a href="/A374912/b374912.txt">Table of n, a(n) for n = 1..10000</a> %F A374912 a(n) == 7 (mod 12) for n>1. - _Hugo Pfoertner_, Jul 24 2024 %t A374912 Select[Prime[Range[1000]], PowerMod[# - 1, #, 2*# - 1] == # &] (* _Paolo Xausa_, Jul 24 2024 *) %o A374912 (Magma) [p: p in PrimesUpTo(10^4) | (p-1)^p mod (2*p-1) eq p]; %o A374912 (PARI) list(lim)=my(v=List([3])); forprimestep(p=7,lim\1,12, if(Mod(p-1,2*p-1)^p==p, listput(v,p))); Vec(v) \\ _Charles R Greathouse IV_, Jul 23 2024 %Y A374912 Aside from the first term, a subsequence of A068229. %Y A374912 Cf. A374913, A374914. %K A374912 nonn %O A374912 1,1 %A A374912 _Juri-Stepan Gerasimov_, Jul 23 2024