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 A215591 #22 Aug 21 2012 09:55:16 %S A215591 0,1,2,3,0,4,1,5,2,6,3,0,7,4,1,8,5,2,9,6,3,0,10,7,4,1,11,8,5,2,12,9,6, %T A215591 3,13,0,10,7,4,14,1,11,8,5,15,2,12,9,6,16,3,13,0,10,7,17,4,14,1,11,8, %U A215591 18,5,15,2,12,9,19,6,16,3,13 %N A215591 Value of x in the n-th number of the form x+y*(3+sqrt(13))/2. %C A215591 Differs from A025639 first at n=308 and n=309, next at n=322 and n=323. - _R. J. Mathar_, Aug 21 2012 %H A215591 Peter G. Anderson, <a href="/A215591/b215591.txt">Table of n, a(n) for n = 1..584</a> %Y A215591 A215592 is the value of y. %K A215591 nonn %O A215591 1,3 %A A215591 _Peter G. Anderson_, Aug 16 2012