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A033921 Largest proper substring of 2^n that is a power of 2 (0 if none). 15
0, 0, 0, 0, 1, 2, 4, 8, 2, 2, 4, 8, 4, 8, 16, 32, 0, 2, 4, 8, 8, 2, 4, 8, 16, 32, 64, 8, 8, 8, 8, 64, 4, 8, 8, 8, 8, 8, 8, 8, 16, 32, 8, 8, 16, 32, 64, 32, 8, 4, 8, 8, 4, 4, 8, 8, 4, 8, 8, 64, 8, 8, 16, 8, 16, 32, 64, 64, 8, 8, 16, 32, 64, 32, 8, 16, 32, 64, 4, 8, 8, 16, 32, 64, 16, 32, 64, 8, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

LINKS

Robert Israel, Table of n, a(n) for n = 0..10000

EXAMPLE

2^15={32}768, so a(15)=32.

MAPLE

for n from 0 to 100 do

L[n]:= sprintf("%d", 2^n);

A[n]:= 0;

for k from n-1 by -1 to 0 do

  if StringTools[Search](L[k], L[n]) <> 0 then

    A[n]:= 2^k; break

  fi

od

od:

seq(A[n], n=0..100); # Robert Israel, Aug 16 2018

CROSSREFS

Cf. A000079.

Sequence in context: A197282 A215452 A175131 * A167420 A195711 A200610

Adjacent sequences:  A033918 A033919 A033920 * A033922 A033923 A033924

KEYWORD

nonn,base

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Patrick De Geest, Jun 15 1998

STATUS

approved

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Last modified May 17 09:03 EDT 2021. Contains 343969 sequences. (Running on oeis4.)