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 A234005 #9 Dec 23 2013 12:37:42 %S A234005 1,1,3,5,12,21,33,81,177,338,667,1178,2031,4105,6872,20569,42744, %T A234005 84457,167863,315633,590081,1325032,2366125,4408350,8146016,16474904, %U A234005 30266484,67320433,112454976,230099960,417825921,1333610936,2714234540,5411487988,10800172911 %N A234005 Number of binary words of length n avoiding the subword given by the binary expansion of n. %H A234005 Alois P. Heinz, <a href="/A234005/b234005.txt">Table of n, a(n) for n = 0..1000</a> %e A234005 a(0) = 1: the empty word. %e A234005 a(1) = 1: 0. %e A234005 a(2) = 3: 00, 01, 11. %e A234005 a(3) = 5: 000, 001, 010, 100, 101. %e A234005 a(4) = 12: 0000, 0001, 0010, 0011, 0101, 0110, 0111, 1010, 1011, 1101, 1110, 1111. %Y A234005 Main diagonal of A209972. %Y A234005 Column k=0 of A233940. %K A234005 nonn %O A234005 0,3 %A A234005 _Alois P. Heinz_, Dec 18 2013