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 A221669 #35 Feb 12 2024 08:39:29 %S A221669 139129,83521,319225,360721,180625,529,42025,277729,222121 %N A221669 3 x 3 magic square containing seven squares, read by rows. %C A221669 Apart from trivial modifications, this is the only known 3 x 3 magic square containing seven squares. No 3 x 3 magic square containing eight or nine squares is known. %C A221669 The seven integer square roots are A221670. %H A221669 A. Bremner, <a href="http://matwbn.icm.edu.pl/ksiazki/aa/aa88/aa8837.pdf">On squares of squares</a>, Acta Arith. 88 (1999), 289-297. %H A221669 A. Bremner, <a href="http://www.multimagie.com/Bremner2.pdf">On squares of squares. II</a>, Acta Arith. 99 (2001), 289-308. %H A221669 John P. Robertson, <a href="https://web.archive.org/web/20180831175909/http://www.jpr2718.org/msofsq.pdf">Magic squares of squares</a>, Math. Mag., 69 (1996), 289-293. %H A221669 Zentralblatt, <a href="http://www.zentralblatt-math.org/zmath/en/advanced/?q=an:01680967&type=pdf&format=complete">Review of "On squares of squares. II" by A. Bremner</a> %H A221669 <a href="/index/Mag#magic">Index entries for sequences related to magic squares</a> %F A221669 a(1) = 139129 = 373^2, a(2) = 83521 = 289^2, a(3) = 319225 = 565^2, a(5) = 180625 = 425^2, a(6) = 529 = 23^2, a(7) = 42025 = 205^2, a(8) = 277729 = 527^2. %e A221669 [139129 83521 319225 %e A221669 360721 180625 529 %e A221669 42025 277729 222121] %Y A221669 Cf. A221670, A319589. %K A221669 nonn,tabf,fini,full %O A221669 1,1 %A A221669 _Jonathan Sondow_, Jan 21 2013