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A059326
Numbers k such that 2*3^k + 7 is prime.
1
1, 3, 9, 11, 15, 17, 24, 41, 68, 72, 641, 716, 1139, 1200, 1661, 3339, 5181, 68769
OFFSET
1,2
COMMENTS
a(18) > 26240. - Jinyuan Wang, Jan 20 2020
a(19) > 100000. - Michael S. Branicky, Jul 08 2024
MATHEMATICA
Do[ If[ PrimeQ[ 2*3^n + 7 ], Print[n] ], {n, 0, 10000} ]
PROG
(PARI) is(n)=ispseudoprime(2*3^n+7) \\ Charles R Greathouse IV, Jun 13 2017
(Magma) [n: n in [0..1000] | IsPrime(2*3^n+7)]; // Jinyuan Wang, Jan 20 2020
CROSSREFS
Cf. A059454 (2*3^k - 7 is prime).
Sequence in context: A075720 A106373 A190226 * A370873 A028312 A310315
KEYWORD
nonn,more
AUTHOR
Robert G. Wilson v, Feb 15 2001
EXTENSIONS
a(18) from Michael S. Branicky, Jul 07 2024
STATUS
approved