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 A188638 #8 Sep 01 2014 09:05:09 %S A188638 1,8,9,4,0,0,6,6,5,3,5,4,7,6,8,0,5,9,0,9,4,2,4,3,8,0,7,8,8,8,2,0,5,6, %T A188638 3,7,8,1,9,0,4,9,6,4,5,8,8,3,9,4,2,7,3,9,2,2,1,6,6,4,2,2,4,1,9,3,4,5, %U A188638 2,8,7,0,8,7,1,5,9,9,8,7,0,4,4,8,1,9,9,1,1,9,9,9,9,8,6,0,3,0,2,2,8,9,4,7,8,0,6,6,4,1,8,6,7,6,6,7,1,8,6,4,5,1,1,1,2,9,3,7,6,2 %N A188638 Decimal expansion of length/width of a meta-1st electrum rectangle. %C A188638 See A188618 for the definition of 1st electrum rectangle. Briefly, it is a rectangle such that the removal of a golden rectangle from one end leaves a silver rectangle. %H A188638 Clark Kimberling, <a href="http://www.jstor.org/stable/27963362">A Visual Euclidean Algorithm</a>, The Mathematics Teacher 76 (1983) 108-109. %t A188638 t=(1+3^(1/2))/2; r=(t+(t^2+4)^(1/2))/2 %t A188638 FullSimplify[r] %t A188638 N[r, 130] %t A188638 RealDigits[N[r, 130]][[1]] %Y A188638 Cf. A188618, A188619, A188639. %K A188638 nonn,cons %O A188638 1,2 %A A188638 _Clark Kimberling_, Apr 06 2011