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 A015898 #13 Oct 23 2018 05:44:02 %S A015898 1,2,3,6,9,10,18,30,90,123,730,7086,172426,300243,372390,449674, %T A015898 1812298,5027914,5307130,17214354,20788426,84929451,101992426, %U A015898 102177370,103544442,106494770,161388338,181327546,193710249,207083626 %N A015898 Numbers k such that k | 9^k + 9. %H A015898 Giovanni Resta, <a href="/A015898/b015898.txt">Table of n, a(n) for n = 1..100</a> %t A015898 Select[Range[10^5], Mod[PowerMod[9, #, #] + 9, #] == 0 &] (* _Giovanni Resta_, Oct 23 2018 *) %Y A015898 Cf. A006517, A015888, A015889, A015891, A015892, A015893, A015897, A015902, A015903, A015904, A015905, A015906. %K A015898 nonn %O A015898 1,2 %A A015898 _Robert G. Wilson v_ %E A015898 Missing a(2)-a(4) from _Giovanni Resta_, Oct 23 2018