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A023415 If any power of 2 ends with k 8's and 9's, they must be the first k terms of this sequence in reverse order. 5
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

1,1

COMMENTS

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

LINKS

Ray Chandler, Table of n, a(n) for n = 1..10000

PROG

(Python)

# upper limit of backward value of 2^n

a, i=8, 0; x=a

while i < 200:

     i+=1; print(x, end=', ')

     if a%2**(i+1) == 0: x=8

     else: x=9

     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 October 6 23:36 EDT 2022. Contains 357270 sequences. (Running on oeis4.)