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 A165564 #24 Nov 16 2017 02:46:30
%S A165564 1,2,3,4,8,9,10,11,12,16,17,18,19,25,26,27,32,33,35,36,40,42,43,44,48,
%T A165564 49,50,51,57,58,59,64,66,67,68,72,73,74,75,76,81,82,83,89,90,91,97,98,
%U A165564 99,100,104,105,106,107,108,113,114,115,121,122,123,128,129,130
%N A165564 Numbers which are not congruent numbers, i.e., positive integers which are not the area of any right triangle with rational sides.
%C A165564 It is known that every positive integer is the area of some triangle with rational sides. See the survey by Top and Yui. - _Jonathan Sondow_, Nov 15 2017
%D A165564 Alter, Ronald; Curtz, Thaddeus B.; Kubota, K. K. Remarks and results on congruent numbers. Proceedings of the Third Southeastern Conference on Combinatorics, Graph Theory and Computing (Florida Atlantic Univ., Boca Raton, Fla., 1972), pp. 27-35. Florida Atlantic Univ., Boca Raton, Fla., 1972. MR0349554 (50 #2047). - From _N. J. A. Sloane_, Apr 28 2012
%H A165564 Michel Marcus, <a href="/A165564/b165564.txt">Table of n, a(n) for n = 1..4258</a>
%H A165564 Boris Iskra, <a href="http://dx.doi.org/10.3792/pjaa.72.168">Non-congruent numbers with arbitrarily many prime factors congruent to 3 modulo 8</a>, Proc. Japan Acad. Ser. A Math. Sci., Volume 72, Number 7 (1996), 168-169.
%H A165564 J. Top and N. Yui, <a href="https://www.math.leidenuniv.nl/~psh/ANTproc/19yui.pdf">Congruent number problems and their variants</a>, Mathematical Sciences Research Institute Publications, 44 (2008), 613-639.
%F A165564 Integers \ { A003273 }.
%Y A165564 Complement of A003273.
%K A165564 nonn
%O A165564 1,2
%A A165564 Jose Brox (brox(AT)agt.cie.uma.es), Sep 22 2009
%E A165564 Name corrected by _Jonathan Sondow_, Nov 15 2017