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A320909
Numbers k such that k^2 and k^3, when reversed, are prime.
1
89, 271, 325, 328, 890, 1025, 1055, 1081, 1129, 1169, 1241, 2657, 2710, 3112, 3121, 3149, 3244, 3250, 3263, 3280, 3335, 3346, 3403, 4193, 4222, 4231, 4289, 4291, 5531, 5584, 5653, 5678, 5716, 5791, 5795, 5836, 5837, 8882, 8900, 8926, 8942, 9664, 9794, 9875
OFFSET
1,1
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000 (first 100 terms from Jesse Endo Jenks)
EXAMPLE
89 is a term since 89^2 = 7921 and 1297 is prime, and 89^3 = 704969 and 969407 is prime.
MATHEMATICA
Select[Range[10^4], AllTrue[IntegerReverse@ {#^2, #^3}, PrimeQ] &] (* Michael De Vlieger, Oct 23 2018 *)
PROG
(PARI) isok(n) = isprime(fromdigits(Vecrev(digits(n^2)))) && isprime(fromdigits(Vecrev(digits(n^3)))); \\ Michel Marcus, Oct 23 2018
(Python)
from sympy import isprime
A320909_list = [n for n in range(1, 10**6) if isprime(int(str(n**2)[::-1])) and isprime(int(str(n**3)[::-1]))] # Chai Wah Wu, Jan 24 2019
CROSSREFS
Intersection of A059007 and A059008.
Sequence in context: A140040 A008900 A238681 * A227519 A142393 A142045
KEYWORD
nonn,base
AUTHOR
Jesse Endo Jenks, Oct 23 2018
STATUS
approved