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 A094807 #8 Apr 30 2014 01:37:54 %S A094807 12,60,120,168,360,420,660,1008,1092,1260,1680,1848,1980,2448,2640, %T A094807 2772,3120,3420,3432,4620,4680,5148,5460,6072,7140,7800,8160,8580, %U A094807 9240,9828,10032,11220,11628,12180,13260,14280,14880,15708,15912,15960,17940 %N A094807 Numbers n such that primitive solutions for 1/n^2 = 1/x^2 + 1/y^2 exist. %C A094807 Numbers n that are the product of two legs of a primitive Pythagorean triangle, that is, n = 2xy(x^2-y^2) where x and y are two relatively prime positive integers of different parity and x is greater than y. %C A094807 Numbers n which are the length of the altitude on the hypotenuse of a Pythagorean triangle and the smallest in its similarity class. %D A094807 E. Bahier, Recherche Methodique et Proprietes des Triangles Rectangles en Nombres Entiers, Hermann, Paris, 1916. p. 68. %F A094807 Equals 2*A024365(n). %e A094807 12 is in the sequence because we have 1/12^2 = 1/15^2 + 1/20^2 and gcd(12,15,20)=1. %K A094807 nonn %O A094807 1,1 %A A094807 _Lekraj Beedassy_, Jun 11 2004 %E A094807 Comments provided by _Michael Somos_, Oct 01 2004