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A122727
Numbers k such that abs(9^k - 2^11) is prime.
0
1, 3, 4, 6, 15, 153, 159, 166, 832, 1123, 1294, 4408, 14854, 24864, 33420, 36529, 45754
OFFSET
1,2
COMMENTS
a(13) > 10^4, if it exists. - Amiram Eldar, Jul 03 2024
LINKS
Ivars Peterson, Prime Talent, MathTrek, Science News Online, July 6, 1998. [Wayback Machine link]
EXAMPLE
For k = 1, abs(9^1-2^11) = 2039 which is prime. So 1 is the first term.
MATHEMATICA
Select[Range[1300], PrimeQ[Abs[9^#-2^11]]&] (* Harvey P. Dale, Apr 20 2022 *)
PROG
(PARI) g(n) = for(x=1, n, y=abs(9^x-2^11); if(ispseudoprime(y), print1(x", ")))
CROSSREFS
Sequence in context: A308533 A369735 A322956 * A347056 A089249 A173944
KEYWORD
nonn,more
AUTHOR
Cino Hilliard, Sep 23 2006
EXTENSIONS
a(12) from Amiram Eldar, Jul 03 2024
a(13)-a(17) from Michael S. Branicky, Jul 03 2024
STATUS
approved