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A349031
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The "Fouriest" numbers: numbers that can be expressed as a string of 4's longer than the original number in some base.
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1
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624, 3124, 6220, 15624, 37324, 78124, 78432, 223948, 390624, 549028, 1343692, 1953124, 3843200, 8062156, 9586980, 9765624, 26902404, 48372940, 48828124, 76695844, 188316832, 244140624, 290237644, 613566756, 1220703124, 1318217828, 1741425868, 4908534052
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OFFSET
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1,1
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COMMENTS
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Inspired by Saturday Morning Breakfast Cereal comics.
The "Fouriest" numbers. The number shown in the comment, 624, is correctly identified as a term of the sequence.
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LINKS
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EXAMPLE
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624 is a member of this sequence because 624 expressed in base 5 is 4444. 4444 has 4 digits and 624 has only 3.
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PROG
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(Python)
from math import log
super_fours = []
for length in range(4, int(log(limit, 5))+1):
fours = "4"*length
for base in range(5, 10):
keep = 4*(1-base**length)//(1-base)
if len(str(keep)) < len(fours) and keep < limit:
super_fours.append(keep)
return sorted(super_fours)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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