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 A190896 #8 Dec 30 2012 07:45:59
%S A190896 1,2,3,4,8,10,13,15,16,19,20,32,35,37,38,40,49,54,61,64,67,68,73,74,
%T A190896 79,80,85,87,93,103,117,121,127,128,131,134,136,139,141,143,148,151,
%U A190896 152,155,156,158,160,165,166,170,172,174,182,193,197,217,218,239,241,251,256,259,262,264,267,268
%N A190896 Least positive integer whose binary representation does not occur in the concatenation of the binary representations of all earlier terms.
%C A190896 See the variant A118250 for comments and examples.
%o A190896 (PARI) A190896(n,show=0,a=1)={my(c=[0],S=[],L); for(k=1,n, show && print1(a","); while( setsearch(S,binary(a++)),); c=concat(c,binary(a)); S=[]; for(i=0,#c-L=#binary(a), c[i+1] & for(j=i+L,min(i+L+1,#c), S=setunion(S,Set(t=[vecextract(c,2^j-2^i)])))));a}
%Y A190896 Cf. A190897 (concatenation of binary representations), A118248 (the same with nonnegative integers), A118250, A118252 (variants where binary representations are reversed).
%K A190896 easy,nonn,base
%O A190896 0,2
%A A190896 _M. F. Hasler_, Dec 29 2012