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A093713
Numbers k such that 6^k - 5^(k-1) is prime.
15
1, 2, 3, 4, 5, 12, 16, 18, 21, 42, 66, 69, 123, 132, 165, 204, 397, 401, 486, 657, 1005, 1050, 1882, 2545, 2813, 3168, 4092, 4151, 4469, 5358, 9168, 11554, 11866, 80946
OFFSET
1,2
COMMENTS
a(35) > 10^5. - Robert Price, May 04 2016
MATHEMATICA
Do[ If[ PrimeQ[6^n - 5^(n - 1)], Print[n]], {n, 2000}]
PROG
(PARI) is(n)=isprime(6^n-5^(n-1)) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
Cf. A093765.
Sequence in context: A306077 A329793 A103651 * A057472 A333390 A367408
KEYWORD
nonn,more
AUTHOR
Herman H. Rosenfeld (herm3(AT)pacbell.net) and Robert G. Wilson v, Jun 17 2004
EXTENSIONS
a(24)-a(34) from Robert Price, May 04 2016
STATUS
approved