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A023415 If any power of 2 ends with k 8's and 9's, they must be the first k elements of this sequence in reverse order. 4
8, 8, 8, 9, 8, 9, 9, 8, 9, 8, 9, 8, 8, 9, 9, 8, 9, 8, 9, 9, 9, 8, 8, 8, 8, 9, 8, 8, 8, 8, 9, 9, 9, 9, 8, 9, 8, 8, 9, 9, 8, 8, 9, 9, 8, 9, 8, 8, 9, 8, 9, 8, 9, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 8, 9, 8, 8, 8, 9, 9, 8, 8, 9, 8, 8, 9, 9, 8, 8, 9, 9, 9, 8, 9, 9, 9, 9, 9, 9, 8, 8, 9, 8, 8, 9, 9, 9, 9, 9, 9, 8, 8, 8, 9, 9, 8, 8, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Upper limit of backward value of 2^n and n!. - Simon Plouffe, Mar 23 2009

LINKS

Table of n, a(n) for n=0..107.

PROG

(Python)

# upper limit of backward value of 2^n

a, i=8, 0; x=a

while 1:

     i+=1; print x, ', ' ,

     if a%2**(i+1) == 0: x=8

     else: x=9

     a=a+x*10**i

# Cezary Glowacz, Mar 11 2017

CROSSREFS

Sequence in context: A248762 A186985 A203127 * A294659 A134314 A242891

Adjacent sequences:  A023412 A023413 A023414 * A023416 A023417 A023418

KEYWORD

nonn,base

AUTHOR

David W. Wilson

STATUS

approved

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Last modified November 14 15:30 EST 2018. Contains 317209 sequences. (Running on oeis4.)