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A181987 Numbers n such that (39^n - 1)/38 is prime. 1
349, 631, 4493, 16633, 36341 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Harvey Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.
MATHEMATICA
Select[Prime[Range[100000]], PrimeQ[(39^#-1)/38]&]
PROG
(PARI) is(n)=ispseudoprime((39^n-1)/38) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A230609 A177174 A139658 * A054824 A031420 A273530
KEYWORD
hard,more,nonn
AUTHOR
Robert Price, Apr 04 2012
STATUS
approved

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Last modified July 13 02:22 EDT 2024. Contains 374259 sequences. (Running on oeis4.)