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 A120339 #9 Mar 30 2012 18:54:34 %S A120339 30,195,870,1326,9078,29406,37830,62211,188355,426390,998790,1756950, %T A120339 2922510,8430270,20031171,33929310,41996670,57206526,82401006, %U A120339 137295678,216148803,941038566,1152597606,1418915886,1879906755,2668548675,3870146310,6449974275,9365063430,18263765550,39154389150,44208781350 %N A120339 a(n) = 3abc, where (a,b,c) is a Markoff triple. The first Markoff triple considered is (1,2,5) and the ordering is increasing. %H A120339 Tom Ace, <a href="http://www.minortriad.com/markoff.html">Markoff numbers</a>. %H A120339 Simone Severini, <a href="http://www.homepages.ucl.ac.uk/~ucapsse">Homepage</a>. %Y A120339 Cf. A002559. %K A120339 nonn %O A120339 1,1 %A A120339 _Simone Severini_, Jun 22 2006 %E A120339 Corrected and extended by _T. D. Noe_, Jan 28 2011