A030001 - OEIS

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

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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