A046289 Numbers k such that 2^k contains 2^3=8 as its largest proper substring of the form 2^m (probably finite).

7, 11, 13, 19, 20, 23, 27, 28, 29, 30, 33, 34, 35, 36, 37, 38, 39, 42, 43, 48, 50, 51, 54, 55, 57, 58, 60, 61, 63, 68, 69, 74, 79, 80, 87, 88, 90, 91, 93, 94, 113, 115, 121, 128, 130, 139, 149, 150, 168, 169, 172, 173, 174, 187, 229, 337, 338, 376, 417

Offset: 1

Author

Patrick De Geest, Jun 15 1998

Keywords

• nonn
• base

Crossrefs

Cf. A033921.

Programs

Mathematica

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 *)