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 A227197 #9 Jul 20 2019 08:08:40 %S A227197 2,4,6,8,9,10,12,14,15,16,18,20,22,24,25,26,28,30,32,33,34,36,38,39, %T A227197 40,42,44,46,48,49,50,52,54,56,57,58,60,62,63,64,66,68,70,72,74,76,78, %U A227197 80,81,82,84,86,87,88,90,92,94,95,96,98,100,102,104,105,106 %N A227197 Integers k for which the first non-one value of Kronecker symbols K(1,k), K(2,k), ..., K(u,k) is 0, not -1. %C A227197 Contains all even numbers >= 2. A227198 gives the odd terms. %C A227197 Gives all k such that A020639(k) = A227196(k). %o A227197 (PARI) A227196(n) = for(k=1,n,if(kronecker(k,n)<1,return(k))) %o A227197 for(n=2,500,if((0==kronecker(A227196(n),n)),print1(n,", "))) %Y A227197 Cf. A227196, A227198. %K A227197 nonn %O A227197 1,1 %A A227197 _Antti Karttunen_, Jul 06 2013