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 A308982 #18 Aug 09 2019 01:55:23 %S A308982 1,2,4,3,6,4,9,8,12,5,10,16,15,6,12,20,18,7,25,24,14,21,30,8,28,16,36, %T A308982 24,35,32,9,18,42,40,27,36,49,48,10,20,45,30,56,40,54,11,22,50,64,33, %U A308982 63,60,44,12,72,55,24,70,36,66,48,81,80,60,13,77,26,39 %N A308982 Areas of integer rectangles circumscribed by increasingly large circles. %C A308982 Sort all rectangles with integer side lengths by the radius of the circle that circumscribes them. Ties are broken by sorting by area. The terms of the sequence are the areas of the rectangles. %e A308982 a(1) is a 1 X 1 rectangle; r = sqrt(1^2 + 1^2) = sqrt(2); A = 1. %e A308982 a(2) is a 2 X 1 rectangle; r = sqrt(2^2 + 1^2) = sqrt(5); A = 2. %t A308982 Times @@@ Take[Flatten[ SortBy[#, Times @@ # &] & /@ GatherBy[ SortBy[ Union[Sort /@ Tuples[ Range[70], 2]], Total[#^2] &], Total[#^2] &], 1], 70] (* _Giovanni Resta_, Jul 18 2019 *) %Y A308982 Cf. A024509. %K A308982 nonn %O A308982 1,2 %A A308982 _Dave Rutt_, Jul 04 2019 %E A308982 More terms from _Giovanni Resta_, Jul 17 2019