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 A134857 #7 Sep 25 2013 02:19:38 %S A134857 241920,1048320,10200960,25724160,37255680,93139200,123963840, %T A134857 245044800,588107520,819786240,1407893760,1871251200,3758169600, %U A134857 5886558720,8553283200,10783342080,13470367680,19769460480,30791819520,40446806400 %N A134857 Numbers that can be written as (a^2-1)(b^2-1) in four or more distinct ways. %C A134857 Subsequence of A134856. Contains A134858 as a subsequence. %H A134857 MathPages, <a href="http://www.mathpages.com/home/kmath275.htm">Numbers Expressible As (a^2-1)(b^2-1)</a>. %e A134857 241920 = (4^2-1)(127^2-1) = (7^2-1)(71^2-1) = (9^2-1)(55^2-1) = (17^2-1)(29^2-1). %Y A134857 Cf. A134856, A134858. %Y A134857 Cf. A057535, A063066, A063067, A063068. %K A134857 easy,nonn %O A134857 1,1 %A A134857 _Herman Beeksma_, Nov 13 2007