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A350442
Numbers m such that 8^m reversed is prime.
5
8, 15, 50, 552, 668, 1011, 1163, 1215, 2199, 4230, 7231, 34310
OFFSET
1,1
COMMENTS
From Bernard Schott, Jan 30 2022: (Start)
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)
MATHEMATICA
Select[Range[2200], PrimeQ[IntegerReverse[8^#]] &] (* Amiram Eldar, Dec 31 2021 *)
PROG
(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
CROSSREFS
Cf. Numbers m such that k^m reversed is prime: A057708 (k=2), A350441 (k=4), A058993 (k=5), A058994 (k=7), A058995 (k=13).
Sequence in context: A216443 A331463 A362906 * A151792 A243295 A118526
KEYWORD
nonn,base,more
AUTHOR
Mohammed Yaseen, Dec 31 2021
EXTENSIONS
a(10)-a(12) from Amiram Eldar, Dec 31 2021
STATUS
approved