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 A262281 #15 Sep 21 2015 14:28:37 %S A262281 3,0,3,0,3,3,5,0,3,3,3,6,5,7,5,0,3,3,3,5,3,3,7,6,5,5,7,7,5,9,5,0,3,3, %T A262281 3,5,3,3,5,5,3,3,3,6,7,7,9,6,5,5,5,5,7,7,7,9,5,5,9,9,5,9,5,0,3,3,3,5, %U A262281 3,3,5,5,3,3,3,6,5,7,5,5,3,3,3,6,3,3,7 %N A262281 a(n) = smallest nonnegative number, not a power of 2, that is not a substring of n in its binary representation. %C A262281 Similar to A261922, but if the smallest missing number is a power of 2, ignore it and look at the next-smallest missing number. %C A262281 This is like applying A261922 not to n itself but to n plus a very large power of 2. Suggested by considering A261416. %H A262281 Hiroaki Yamanouchi, <a href="/A262281/b262281.txt">Table of n, a(n) for n = 0..10000</a> %e A262281 For n = 13 = 1101_2, we can see 0, 11 (3), 101 (5), 110 (6), but not 111 (7), so a(13)=7. %Y A262281 Cf. A261416, A261461, A261922. %Y A262281 See A262289 for the "positive" version. %K A262281 nonn,base %O A262281 0,1 %A A262281 _N. J. A. Sloane_, Sep 17 2015 %E A262281 a(23)-a(86) from _Hiroaki Yamanouchi_, Sep 20 2015