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 A105521 #17 Aug 07 2020 14:43:36 %S A105521 18,60,100,140,270,280,294,462,648,728,756,1078,1080,1210,1496,1530, %T A105521 1584,1768,2028,2090,2574,2772,2860,2990,3150,3588,3910,4550,4624, %U A105521 4680,4950,5434,5670,5984,6498,6960,7140,7548,8330,8398,8432,8436,8820,9568,10098 %N A105521 Sums of area and perimeter of primitive Pythagorean triples. %H A105521 Douglas Butler, <a href="https://www.tsm-resources.com/tsm/lists/trip.html">Table of Pythagorean triples up to 2100</a>, Oundle School iCT Training Centre %H A105521 Ron Knott, <a href="http://www.maths.surrey.ac.uk/hosted-sites/R.Knott/Pythag/pythag.html#anyint">Pythagorean triples</a>. %Y A105521 Cf. A103605, A103606, A024364, A024406, A105520 %K A105521 easy,nonn %O A105521 1,1 %A A105521 _Alexandre Wajnberg_, May 02 2005 %E A105521 Corrected and extended by _Harvey P. Dale_, Oct 27 2018