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 A105831 #5 Jun 17 2018 18:47:15 %S A105831 1,6,7,3,4,15,19,8,11,10,21,13,18,16,2,5,12,9,30,24,54,33,17,26,43,28, %T A105831 71,39,32,55,87,46,25,66,27,93,22,56,78,23,31,114,40,74,36,38,68,106, %U A105831 60,166,42,124,110,14,48,62,85,58,143,86,57,29,140,169,51,118,45,52,76,128 %N A105831 For n>2, a(n) not appeared previously is such that a(n-1)^2+4*a(n-2)*a(n) is a minimal square, a(1)=1, a(2)=6. %H A105831 Ivan Neretin, <a href="/A105831/b105831.txt">Table of n, a(n) for n = 1..10000</a> %Y A105831 Cf. A105822, A105828-A105836. %K A105831 nonn %O A105831 1,2 %A A105831 _Zak Seidov_, Apr 22 2005