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URL: https://oeis.org/A138048

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A138048
Numbers k such that 15^k + 2 is prime.
7
0, 1, 2, 4, 5, 10, 11, 16, 20, 52, 75, 106, 112, 132, 371, 3264, 3424, 5477, 7516, 10365, 44557, 150706
OFFSET
1,3
COMMENTS
No further terms < 100000. - Ray Chandler, Aug 05 2011
a(23) > 2*10^5. - Robert Price, Jun 23 2015
LINKS
Henri & Renaud Lifchitz, PRP Records.
MATHEMATICA
Do[ f = 15^n + 2; If[ PrimeQ[ f ], Print[ {n, f} ] ], {n, 1, 371} ]
PROG
(PARI) is(n)=ispseudoprime(15^n+2) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
Cf. A051783 (k such that 3^k + 2 is prime).
Cf. A087885 (k such that 5^k + 2 is prime).
Sequence in context: A004792 A167795 A322068 * A376589 A057762 A109511
KEYWORD
nonn,more
AUTHOR
Alexander Adamchuk, Mar 02 2008
EXTENSIONS
a(16)-a(19) from Ray Chandler, Jul 30 2011
a(20) found by Lelio R Paula, Dec 2006
a(21) from Ray Chandler, Jul 31 2011
a(22) from Robert Price, Jun 23 2015
STATUS
approved