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A350442
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Numbers m such that 8^m reversed is prime.
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5
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8, 15, 50, 552, 668, 1011, 1163, 1215, 2199, 4230, 7231, 34310
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OFFSET
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1,1
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COMMENTS
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If k is a term, then u = 3*k is a term of A057708, because 8^k = 2^(3k).
If k is an even term, then t = 3*k/2 is a term of A350441, because 8^k = 4^(3k/2). First examples: k = 8, 50, 552, 668, 4230, 34310, ... and corresponding t = 12, 75, 828, 1002, 6345, 51465, ... (End)
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LINKS
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MATHEMATICA
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Select[Range[2200], PrimeQ[IntegerReverse[8^#]] &] (* Amiram Eldar, Dec 31 2021 *)
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PROG
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(PARI) isok(m) = isprime(fromdigits(Vecrev(digits(8^m))))
(Python)
from sympy import isprime
m = 8
for n in range (1, 2000):
if isprime(int(str(m)[::-1])):
print(n)
m *= 8
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CROSSREFS
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KEYWORD
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nonn,base,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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