A030001 Smallest power of 2 whose decimal expansion contains n.

1024, 1, 2, 32, 4, 256, 16, 32768, 8, 4096, 1024, 1099511627776, 128, 131072, 262144, 2097152, 16, 134217728, 1073741824, 8192, 2048, 262144, 8796093022208, 2199023255552, 1024, 256, 262144, 32768, 128, 4294967296, 4194304, 131072, 32, 33554432, 134217728, 33554432

Offset

0,1

Links

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Mathematica

a[n_] := (k = 0; While[ !MatchQ[ IntegerDigits[2^k], {___, Sequence @@ IntegerDigits[n], ___}], k++]; 2^k); Table[a[n], {n, 1, 30}](* Jean-François Alcover, Nov 30 2011 *)
Module[{p2=2^Range[0, 50]}, Table[SelectFirst[p2, SequenceCount[ IntegerDigits[ #], IntegerDigits[ n]]>0&], {n, 0, 40}]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 13 2019 *)

Prog

(Haskell)
import Data.List (isInfixOf)
a030001 n = head $ filter ((show n `isInfixOf`) . show) a000079_list
-- Reinhard Zumkeller, Nov 02 2011
(Python)
def a(n):
  k, strn = 0, str(n)
  while strn not in str(2**k): k += 1
  return 2**k
print([a(n) for n in range(36)]) # Michael S. Branicky, Apr 03 2024

Crossrefs

Cf. A030000 (the exponents), A000079.

Sequence in context: A212934 A263168 A336779 * A176764 A351262 A336778

Adjacent sequences: A029998 A029999 A030000 * A030002 A030003 A030004

Keyword

nonn,base,nice,look

Author

N. J. A. Sloane

Extensions

a(30) corrected by Reinhard Zumkeller, Nov 02 2011

a(0) added by N. J. A. Sloane, Jul 04 2017

Status

approved