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 A262289 #14 Sep 21 2015 17:21:28
%S A262289 3,3,3,5,3,3,5,5,3,3,3,6,5,7,5,5,3,3,3,5,3,3,7,6,5,5,7,7,5,9,5,5,3,3,
%T A262289 3,5,3,3,5,5,3,3,3,6,7,7,9,6,5,5,5,5,7,7,7,9,5,5,9,9,5,9,5,5,3,3,3,5,
%U A262289 3,3,5,5,3,3,3,6,5,7,5,5,3,3,3,6,3,3,7
%N A262289 a(n) = smallest positive number, not a power of 2, that is not a substring of n in its binary representation.
%C A262289 Similar to A261461, but if the smallest missing number is a power of 2, ignore it and look at the next-smallest missing number.
%H A262289 Hiroaki Yamanouchi, <a href="/A262289/b262289.txt">Table of n, a(n) for n = 0..10000</a>
%H A262289 David Consiglio, Jr., <a href="/A262289/a262289.txt">Python Program</a>
%t A262289 fQ[m_, n_] := Block[{g}, g[x_] := ToString@FromDigits@IntegerDigits[x, 2]; StringContainsQ[g@ n, g@ m]]; Table[k = 3; While[Or[fQ[k, n] && k < 2 n, IntegerQ@ Log[2, k]], k++]; k, {n, 0, 86}] (* _Michael De Vlieger_, Sep 21 2015 *)
%Y A262289 Cf. A261416, A261461, A261922.
%Y A262289 See A262281 for the "nonnegative" version.
%K A262289 nonn,base
%O A262289 0,1
%A A262289 _N. J. A. Sloane_, Sep 19 2015
%E A262289 a(23)-a(86) from _Hiroaki Yamanouchi_, Sep 20 2015