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A046292 Numbers k such that 2^k contains 2^6=64 as its largest proper substring of the form 2^m.

%I A046292 #18 Oct 14 2019 04:26:47
%S A046292 26,31,46,59,66,67,72,77,83,86,89,92,96,101,106,111,116,119,123,124,
%T A046292 125,126,129,131,136,138,141,142,144,148,152,153,155,157,163,165,166,
%U A046292 171,176,177,178,181,182,183,186,193,194,197,198,199,202,204,205,206
%N A046292 Numbers k such that 2^k contains 2^6=64 as its largest proper substring of the form 2^m.
%C A046292 If there is a term beyond a(747) = 7954, it is larger than 250000. - _Giovanni Resta_, Oct 14 2019
%H A046292 Giovanni Resta, <a href="/A046292/b046292.txt">Table of n, a(n) for n = 1..747</a>
%e A046292 2^26 = 671088{64};
%e A046292 2^31 = 2147483{64}8;
%e A046292 2^46 = 703687441776{64}.
%t A046292 sub2[n_] := Block[{s = ToString[2^n], k = n - 1}, While[k >= 0 && ! StringContainsQ[s, ToString[2^k]], k--]; k]; Select[Range[300], sub2[#] == 6 &] (* _Giovanni Resta_, Oct 14 2019 *)
%Y A046292 Cf. A033921.
%K A046292 nonn,base
%O A046292 1,1
%A A046292 _Patrick De Geest_, Jun 15 1998