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 A261402 #5 Aug 21 2015 13:44:44 %S A261402 12,8,18,80,88,85,84,89,81,87,86,83,82,11,15,50,58,55,54,59,51,57,56, %T A261402 53,52,5,40,48,45,44,49,41,47,46,43,42,4,14,9,19,90,98,95,94,99,91,97, %U A261402 96,93,92,1,100,7,17,70,78,75,74,79,71,77,76,73,72,6,16,60,68,65,64,69,61,67,66,63,62,13,30,38,35,34,39,31,37,36,33,32,3,12,20,28,25,24,29,21,27,26,23,22,2,0 %N A261402 The Mark-Ulam sequence: an erroneous version of A036747. %C A261402 Note that 10 is missing and 12 appears twice (the first 12 refers to "a dozen"). %H A261402 J. C. Mark and S. Ulam, <a href="http://permalink.lanl.gov/object/tr?what=info:lanl-repo/lareport/LA-UR-87-3600-23">A memorable memo</a>, in Los Alamos Science, Special Issue, 1987. %Y A261402 Cf. A000052, A036747. %K A261402 nonn,word,fini,full %O A261402 1,1 %A A261402 _Michel Marcus_ and _N. J. A. Sloane_, Aug 21 2015