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 A152178 #15 Sep 04 2020 04:08:58 %S A152178 3,2,5,2,107,2,3,2,101,2,29,2,3,2,13,2,3626257,2,3,2,7,2,5,2,3,2,1511, %T A152178 2,173,2,3,2,5,2,7,2,3,2,197,2,13,2,3,2,17491,2,18540593,2,3,2,53,2,5, %U A152178 2,3,2,19,2,17,2,3,2,5,2,11,2,3,2,29,2,97,2,3,2,251 %N A152178 Smallest prime factor of G-n, where G is any sufficiently large power tower of 3, e.g., Graham's number. %C A152178 Least prime p such that A240162(p) == n (mod p). - _Jinyuan Wang_, Aug 30 2020 %H A152178 Jinyuan Wang, <a href="/A152178/b152178.txt">Table of n, a(n) for n = 0..100</a> %H A152178 Wikipedia, <a href="https://en.wikipedia.org/wiki/Graham's_number">Graham's number</a> %e A152178 a(2) = 5 because 3^3^3^... - 2 = 0 (mod 5). %Y A152178 Cf. A152177, A240162. %K A152178 nonn %O A152178 0,1 %A A152178 _Karl W. Heuer_, Nov 28 2008