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A046237
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Numbers whose cube is palindromic in base 7.
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1
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0, 1, 2, 4, 8, 16, 50, 100, 200, 344, 688, 1376, 2402, 4804, 9608, 16808, 33616, 67232, 117650, 235300, 470600, 823544, 1647088, 3294176, 5764802, 11529604, 23059208, 40353608, 80707216, 161414432, 282475250, 564950500, 1129901000, 1977326744, 3954653488, 7909306976
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OFFSET
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1,3
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COMMENTS
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Contains triples with base-7 digits 10^k1, 20^k2, 40^k4 for k >= 1, where ^ denotes repeated concatenation. - Michael S. Branicky, Aug 02 2022
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LINKS
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PROG
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(PARI) isok(k) = my(d=digits(k^3, 7)); Vecrev(d) == d; \\ Michel Marcus, Aug 02 2022
(Python)
from itertools import count, islice
from sympy.ntheory import is_palindromic as ispal
def agen(start=0): yield from (k for k in count(start) if ispal(k**3, 7))
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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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EXTENSIONS
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STATUS
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approved
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