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 A009185 #15 Apr 20 2018 16:43:16 %S A009185 12,24,36,40,45,48,56,60,63,72,80,84,90,96,105,108,112,120,126,132, %T A009185 135,140,144,156,160,165,168,176,180,189,192,195,200,204,208,210,216, %U A009185 220,224,225,228,231,240,252,255,260,264,270,272,273,275,276,280,285,288,300,304 %N A009185 Long leg of more than one Pythagorean triangle. %C A009185 If n is in the sequence, k*n is in the sequence for all k > 1. So sequence is union of arithmetic progressions such as numbers of the form 12*k, 40*k, 45*k, ... - _Altug Alkan_, Nov 30 2015 %C A009185 Numbers appearing more than once in A009012. - _Sean A. Irvine_, Apr 20 2018 %Y A009185 Cf. A009012, A009188, A020883, A033942. %K A009185 nonn %O A009185 1,1 %A A009185 _David W. Wilson_