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 A135157 #6 Jan 21 2014 12:30:21 %S A135157 1,0,2,0,3,1,4,0,5,2,6,0,7,3,8,0,9,6,10,0,11,12,12,4,13,24,14,23,15, %T A135157 54,16,91,17,149,18,326,19,484,20,1144,21,1741,22,4015,23,6589,24, %U A135157 14296,25,25299,26,52077,27,97264,28,193781,29,373996,30,733076 %N A135157 Number of primitive (no repeated characters) and irreducible (not the concatenation of generatable strings) strings obtained from abc by iterated repetition of substrings in place. %H A135157 <a href="/index/Do#repeat">Index entries for doubling substrings</a> %Y A135157 Cf. A135473, A135156. %K A135157 nonn %O A135157 0,3 %A A135157 _David Applegate_ and _N. J. A. Sloane_, Feb 15 2008