A138050 - OEIS

A138050

Numbers k such that 23^k + 2 is prime.

0, 11, 39, 323, 12415, 14655, 27679

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OFFSET

1,2

COMMENTS

No further terms < 100000. - Ray Chandler, Aug 03 2011

LINKS

Henri & Renaud Lifchitz, PRP Records.

MATHEMATICA

Do[ f = 23^n + 2; If[ PrimeQ[ f ], Print[ {n, f} ] ], {n, 1, 323} ]

PROG

(PARI) is(n)=ispseudoprime(23^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).

KEYWORD

nonn,more

AUTHOR

EXTENSIONS

a(5)-a(7) from Ray Chandler, Aug 01 2011

STATUS

approved