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A274135 Numbers n such that 6^n + 5^(n+1) is prime. 0
1, 4, 6, 9, 12, 15, 18, 21, 34, 36, 75, 102, 231, 256, 309, 513, 748, 3789, 12378, 36378 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(21) > 10^5.

LINKS

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

MATHEMATICA

Select[Range[0, 100000], PrimeQ[6^n + 5^(n + 1)] &]

PROG

(PARI) is(n)=ispseudoprime(6^n + 5^(n+1)) \\ Charles R Greathouse IV, Jun 10 2016

(PFGW) ABC2 6^$a + 5^($a+1)

a: from 1 to 100000

Charles R Greathouse IV, Jun 10 2016

CROSSREFS

Cf. A093765.

Sequence in context: A157124 A162735 A024675 * A163656 A100915 A144922

Adjacent sequences:  A274132 A274133 A274134 * A274136 A274137 A274138

KEYWORD

nonn,more

AUTHOR

Robert Price, Jun 10 2016

STATUS

approved

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Last modified July 14 19:48 EDT 2020. Contains 335729 sequences. (Running on oeis4.)