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A236371 Numbers n such that 7^n - 12 is prime. 9
2, 3, 4, 12, 27, 28, 34, 36, 147, 179, 242, 276, 278, 466, 735, 2371, 4548, 5606, 10324, 82899 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(21) > 10^5.

LINKS

Table of n, a(n) for n=1..20.

MATHEMATICA

Select[Range[1, 100000], PrimeQ[7^# - 12] &]

PROG

(PARI) for(n=1, 5*10^5, if(isprime(7^n-12), print1(n, ", ")))

CROSSREFS

Cf. A236371, A217131, A191469, A090669, A096305, A217130, A217132, A152213.

Sequence in context: A059810 A037397 A168047 * A333620 A173446 A053350

Adjacent sequences:  A236368 A236369 A236370 * A236372 A236373 A236374

KEYWORD

nonn

AUTHOR

Robert Price, Jan 23 2014

STATUS

approved

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Last modified July 13 13:48 EDT 2020. Contains 335688 sequences. (Running on oeis4.)