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 A254063 #8 Jan 24 2015 15:17:05 %S A254063 5,10,15,17,20,30,34,35,37,40,41,43,45,47,51,55,59,60,65,67,68,70,74, %T A254063 79,80,82,83,86,89,90,94,95,101,102,105,109,110,111,115,118,119,120, %U A254063 123,127,129,130,131,134,135,136,140,141,145,148,151,153,155,158 %N A254063 Positive integers whose square is expressible in exactly one way as x^2 + 5xy + y^2, with 0 < x < y. %H A254063 Colin Barker, <a href="/A254063/b254063.txt">Table of n, a(n) for n = 1..750</a> %e A254063 5 is in the sequence because the only solution to x^2 + 5xy + y^2 = 25 with 0 < x < y is (x,y) = (1,3). %Y A254063 Cf. A084645, A232437, A248599, A254064. %K A254063 nonn %O A254063 1,1 %A A254063 _Colin Barker_, Jan 24 2015