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 A091387 #5 Oct 09 2013 14:20:16 %S A091387 1,4,11,3,11,0,11,4,12,5,7,12,4,11,0,5,11,6,12,4,12,4,6,11,4,6,11,4,9, %T A091387 4,10,2,10,3,8,1,3,6,1,4,6,2,8,9,4,10,2,7,6,11,4,6,9,9,1,9,2,7,12,4, %U A091387 10,1,1,3,8,1,3,6,12,4,5,1,7,8,3,5,10,3,8,1,7,0,2,10,12,2,4,0,6,12,5,0,3,5 %N A091387 Aronson's mod 13 sequence: "T is the first, fourth, eleventh, third, ... letter in this sentence, not counting spaces or commas and all mod 13". %C A091387 Infinite? Periodic? It seems the answers are "Yes and No" because many numbers (such as "tenth") have multiple T's and moreover, in many of these, the T's are spread such that at least one of them will be != 2 mod 13 (2 is important because "second" is the only T-less word) %D A091387 A. J. Aronson, quoted by D. R. Hofstadter in Metamagical Themas, Basic Books, NY, 1985, p. 44. %H A091387 B. Cloitre, N. J. A. Sloane and M. J. Vandermast, <a href="http://www.cs.uwaterloo.ca/journals/JIS/index.html">Numerical analogues of Aronson's sequence</a>, J. Integer Seqs., Vol. 6 (2003), #03.2.2. %Y A091387 Cf. A005224, A091388, A091389, A091390, A091391. %K A091387 easy,nonn,word %O A091387 0,2 %A A091387 _Sam Alexander_, Jan 05 2004