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 A333335 #17 Apr 15 2020 00:12:36 %S A333335 1,2,2,4,1,2,5,8,2,4,10,8,4,6,11,16,13,2,12,4,5,10,22,8,21,4,11,48,28, %T A333335 14,30,32,17,16,31,20,7,12,29,24,40,26,42,68,11,22,44,32,5,44,86,4,52, %U A333335 38,51,48,59,28,50,44,60,30,47,64,4,68,3,16,158,94,70 %N A333335 a(n) is the smallest positive number k such that n divides 4^k + k. %H A333335 Brazil National Olympiad, 2005, <a href="https://artofproblemsolving.com/community/c6h57713">Problem 6</a> %F A333335 a(4^m) = 4^m for m >= 0. %o A333335 (PARI) a(n) = for(k=1, oo, if(Mod(4, n)^k==-k, return(k))); %Y A333335 Cf. A247248, A333334, A333336, A333340. %K A333335 nonn,easy %O A333335 1,2 %A A333335 _Jinyuan Wang_, Apr 14 2020