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 A080949 #8 Mar 30 2012 16:49:42 %S A080949 0,5,10,15,13,18,23,28,33,31,36,41,39,44,42,47,52,50,55,60,65,70,68, %T A080949 73,78,83,88,86,91,96,94,99,97,102,107,105,110,115,113,118,116,114, %U A080949 119,117,122,127,125,130,135,133,138,136,141,146,144,149,154,159 %N A080949 a(1)=0; for n>1, a(n)=a(n-1)-2 if n is already in the sequence, a(n)=a(n-1)+5 otherwise. %H A080949 B. Cloitre, N. J. A. Sloane and M. J. Vandermast, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL6/Cloitre/cloitre2.html">Numerical analogues of Aronson's sequence</a>, J. Integer Seqs., Vol. 6 (2003), #03.2.2. %H A080949 B. Cloitre, N. J. A. Sloane and M. J. Vandermast, <a href="http://arXiv.org/abs/math.NT/0305308">Numerical analogues of Aronson's sequence</a> (math.NT/0305308) %Y A080949 Cf. A080578, A080900, A080901, A080939. %K A080949 nonn %O A080949 1,2 %A A080949 _N. J. A. Sloane_ and Benoit Cloitre, Apr 04 2003