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 A184520 #4 Mar 30 2012 18:57:16
%S A184520 1,2,3,4,5,6,8,9,10,11,12,14,15,16,17,18,20,21,22,23,24,26,27,28,29,
%T A184520 30,32,33,34,35,36,38,39,40,41,42,43,45,46,47,48,49,51,52,53,54,55,57,
%U A184520 58,59,60,61,63,64,65,66,67,69,70,71,72,73,74,76,77,78,79,80,82,83,84,85,86,88,89,90,91,92,94,95,96,97,98,100,101,102,103,104,105,107,108,109,110,111,113,114,115,116,117,119,120,121,122,123,125,126,127,128,129,131,132,133,134,135,136,138,139,140,141,142
%N A184520 Lower s-Wythoff sequence, where s=5n+1. Complement of A184521.
%C A184520 See A184117 for the definition of lower and upper s-Wythoff sequences.
%t A184520 k = 5; r = -1; d = Sqrt[4 + k^2];
%t A184520 a[n_] := Floor[(1/2) (d + 2 - k) (n + r/(d + 2))];
%t A184520 b[n_] := Floor[(1/2) (d + 2 + k) (n - r/(d + 2))];
%t A184520 Table[a[n], {n, 120}]
%t A184520 Table[b[n], {n, 120}]
%Y A184520 Cf. A184117, A184521.
%K A184520 nonn
%O A184520 1,2
%A A184520 _Clark Kimberling_, Jan 16 2011