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A059621
Numbers k such that (5*3^k + 7)/2 is prime.
1
1, 3, 7, 9, 19, 27, 57, 69, 163, 175, 357, 379, 3045, 38425, 70375, 99975
OFFSET
1,2
MATHEMATICA
Do[ If[ PrimeQ[ (5*3^n + 7)/2 ], Print[n] ], {n, 0, 10000} ]
PROG
(PARI) is(n)=ispseudoprime((5*3^n+7)/2) \\ Charles R Greathouse IV, Jun 13 2017
(Magma) [k: k in [0..1000] | IsPrime((5*3^k + 7) div 2)]; // Jinyuan Wang, Jan 28 2020
CROSSREFS
Cf. A059622 ((5*3^k-7)/2 is prime).
Sequence in context: A154508 A073573 A309328 * A034926 A224849 A304128
KEYWORD
nonn,more
AUTHOR
Robert G. Wilson v, Feb 19 2001
EXTENSIONS
a(14) from Michael S. Branicky, May 20 2023
a(15)-a(16) from Michael S. Branicky, Jul 28 2024
STATUS
approved