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 A308012 #10 May 15 2019 22:52:40 %S A308012 1,2,3,6,9,12,15,18,21,24,27,30,33,36,39,41,44,47,50,53,56,59,62,65, %T A308012 68,71,73,76,78,81,84,87,90,93,96,99,102,105,108,111,114,117,120,123, %U A308012 126,129,132,135,138,141,144,147,150,153,156,159,162,165,168 %N A308012 List of x-coordinates of successive points on the middle one of the three lines formed by the terms of A081145. %C A308012 See A081145 and A308009 for further information about the three lines. %H A308012 N. J. A. Sloane, <a href="/A308012/b308012.txt">Table of n, a(n) for n = 1..34254</a> %Y A308012 Cf. A081145, A308009, A308010-A308015. %K A308012 nonn %O A308012 1,2 %A A308012 _N. J. A. Sloane_, May 15 2019