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 A376432 #22 Sep 28 2024 07:55:52 %S A376432 5,7,3,113,3,7,3,5,3,3,373,19,3,11,3,3,3,31,17,3,37,5,3,3,7,3,13,3,5, %T A376432 3,921259,3,3,5,3,19,79,41,3,3,3,7,3,97,3,5,53,7,3,5,3,3,11,3,3,3,3, %U A376432 17,139,3,71,3,7,3,157,3,83,13,3,5,3,3,23,11,5,3,3,199 %N A376432 a(n) is the least odd prime factor of prime(n)^prime(n)+1. %H A376432 Hugo Pfoertner, <a href="/A376432/b376432.txt">Table of n, a(n) for n = 1..12250</a> %F A376432 a(n) = A078701(A125137(n)). - _Michel Marcus_, Sep 27 2024 %e A376432 While almost all terms lie in the range between 3 and (prime(n)+1)/2, there are some notable outliers: a(31) = 921259 with prime(31)=127 (127^127+1=2^7*a(31)*C268), and a(1028)=1528928750837 with prime(1028)=8191 (8191^8191+1=2^13*a(1028)*C32039), Cx being composite with x decimal digits. %o A376432 (PARI) a376432(n) = my(pp=prime(n)^prime(n)+1); forprime (p=3, oo, if(pp%p==0, return(p))) %Y A376432 Cf. A078701, A125137, A376431. %K A376432 nonn %O A376432 1,1 %A A376432 _Hugo Pfoertner_, Sep 27 2024