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 A250043 #19 Jan 29 2015 09:49:00
%S A250043 2,3,4,5,6,7,8,18,20,22,24,26,27,30,33,36,38,40,42,44,45,50,54,56,57,
%T A250043 58,60,62,63,70,72,74,76,78,80,162,164,165,166,168,170,180,182,184,
%U A250043 185,186,188,198,200,202,204,206,216,218,219,220,222,224,234,236
%N A250043 Numbers n such that m = floor(n/9) is not coprime to n and, if nonzero, m is also a term of the sequence.
%C A250043 See the comments in A250041 which all apply, except for the setting of the base, b=9. In particular, they define the property RTNC(b).
%H A250043 Stanislav Sykora, <a href="/A250043/b250043.txt">Table of n, a(n) for n = 1..10000</a>
%H A250043 Stanislav Sykora, <a href="https://oeis.org/wiki/File:GeneticThreads.txt">PARI/GP scripts for genetic threads</a>, with code and comments
%H A250043 Wikipedia, <a href="http://en.wikipedia.org/wiki/Coprime_integers">Coprime integers</a>
%o A250043 (PARI) See the link
%o A250043 (PARI) is_rtnc(n, b=9) = {while (((m=gcd(n\b, n)) != 1), if (m == 0, return (1)); n = n\b;); return (0);} \\ _Michel Marcus_, Jan 17 2015
%Y A250043 Cf. A250041 (b=10), A250042.
%Y A250043 Other lists of right-truncatable numbers with the property RTNC(b): A005823 (b=3), A250037 (b=4), A250039 (b=16), A250045 (b=8), A250047 (b=7), A250049 (b=6), A250051 (b=5).
%K A250043 nonn,base
%O A250043 1,1
%A A250043 _Stanislav Sykora_, Jan 15 2015