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 A081935 #9 Jan 21 2020 12:23:50 %S A081935 4,12,24,40,56,60,72,80,84,112,120,132,140,144,156,168,176,180,208, %T A081935 220,224,240,252,260,264,272,288,304,308,312,340,352,360,364,380,396, %U A081935 408,416,420,420,440,456,460,468,476,480,520,528,532,544,552,572,572,600 %N A081935 Ordered even long legs of primitive Pythagorean triangles. %H A081935 Ray Chandler, <a href="/A081935/b081935.txt">Table of n, a(n) for n = 1..10000</a> %Y A081935 Cf. A020883. %K A081935 nonn %O A081935 1,1 %A A081935 _Lekraj Beedassy_, Apr 23 2003 %E A081935 More terms from _Ray Chandler_, Oct 29 2003