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 A248400 #10 Oct 13 2019 04:18:04 %S A248400 17,89,97,193,217,233,259,305,377,401,449,481,497,617,667,713,745,769, %T A248400 897,929,955,977,979,1009,1011,1027,1033,1049,1065,1337,1345,1355, %U A248400 1385,1409,1417,1489,1507,1555,1739,1769,1771,1801,1803,1817,1921,1945,2001,2019 %N A248400 Noncongruent squarefree numbers n with A248394(n)/d(n) = -2, where d(n) = A000005(n). %H A248400 J. B. Tunnell, <a href="http://dx.doi.org/10.1007/BF01389327">A classical Diophantine problem and modular forms of weight 3/2</a>, Invent. Math., 72 (1983), 323-334. %Y A248400 Cf. A000005, A003273, A248394, A248395, A248397-A248406. %K A248400 nonn %O A248400 1,1 %A A248400 _N. J. A. Sloane_, Oct 20 2014 %E A248400 More terms from _Amiram Eldar_, Oct 13 2019