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 A081804 #10 Jan 26 2020 19:55:43 %S A081804 5,13,17,25,29,37,41,53,61,65,65,73,85,85,89,101,97,113,109,125,145, %T A081804 145,137,149,157,181,173,169,185,197,185,193,221,205,205,229,221,257, %U A081804 233,265,241,269,265,277,293,313,281,325,289,317,305,305,365,325,365,337 %N A081804 Hypotenuses of primitive Pythagorean triangles sorted on semiperimeter. %H A081804 Ray Chandler, <a href="/A081804/b081804.txt">Table of n, a(n) for n = 1..10000</a> %Y A081804 Cf. A020886, A020882. %K A081804 nonn %O A081804 1,1 %A A081804 _Lekraj Beedassy_, Apr 23 2003 %E A081804 Corrected and extended by _Ray Chandler_, Oct 29 2003