A046287 Numbers k such that 2^k contains 2^1=2 as its largest proper substring of the form 2^m (probably finite).
5, 8, 9, 17, 21
Offset: 1
Crossrefs
Cf. A033921.
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.
2^15 = {32}768; 2^25 = 335544{32}; 2^41 = 219902{32}55552.
sub2[n_] := Block[{s = ToString[2^n], k = n - 1}, While[k >= 0 && ! StringContainsQ[s, ToString[2^k]], k--]; k]; Select[Range[2000], sub2[#] == 5 &] (* Giovanni Resta, Oct 14 2019 *)
2^26 = 671088{64}; 2^31 = 2147483{64}8; 2^46 = 703687441776{64}.
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 *)
sub2[n_] := Block[{s = ToString[2^n], k = n - 1}, While[k >= 0 && ! StringContainsQ[s, ToString[2^k]], k--]; k]; Select[Range[1677], sub2[#] == 10 &] (* Giovanni Resta, Oct 14 2019 *)
2^105 = 40564{8192}07303340847894502572032.
sub2[n_] := Block[{s = ToString[2^n], k = n - 1}, While[k >= 0 && ! StringContainsQ[ s, ToString[2^k]], k--]; k]; Select[Range[1513], sub2[#] == 13 &] (* Giovanni Resta, Oct 14 2019 *)
2^4={1}6 and 2^0=1; 2^5=3{2} and 2^1=2; 2^6=6{4} and 2^2=4; etc.
sub2[n_] := Block[{s = ToString[2^n], k = n - 1}, While[k >= 0 && ! StringContainsQ[s, ToString[2^k]], k--]; k]; Select[Range[1000], sub2[#] == 2 &] (* Giovanni Resta, Oct 14 2019 *)
sub2[n_] := Block[{s = ToString[2^n], k = n - 1}, While[k >= 0 && ! StringContainsQ[s, ToString[2^k]], k--]; k]; Select[Range[500], sub2[#] == 3 &] (* Giovanni Resta, Oct 14 2019 *)
2^14 = {16}384; 2^24 = {16}7772{16}; 2^40 = 109951{16}27776.
sub2[n_] := Block[{s = ToString[2^n], k = n - 1}, While[k >= 0 && ! StringContainsQ[s, ToString[2^k]], k--]; k]; Select[Range[2000], sub2[#] == 4 &] (* Giovanni Resta, Oct 14 2019 *)
2^102 = 50706024009129176059868{128}21504.
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