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A217351 Numbers n such that 6^n + 7 is prime. 3
1, 2, 3, 4, 6, 21, 24, 27, 30, 54, 70, 126, 369, 435, 612, 787, 1275, 2155, 2436, 5734, 6016 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..21.

MATHEMATICA

Select[Range[10000], PrimeQ[6^# + 7] &]

PROG

(PARI) is(n)=ispseudoprime(6^n+7) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Cf. A145106, A217352.

Cf. A104115 (associated primes).

Sequence in context: A084391 A259383 A220702 * A274238 A115035 A219048

Adjacent sequences:  A217348 A217349 A217350 * A217352 A217353 A217354

KEYWORD

nonn,more,hard

AUTHOR

Vincenzo Librandi, Oct 02 2012

EXTENSIONS

a(20)-a(21) from Bruno Berselli, Oct 04 2012

STATUS

approved

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Last modified August 13 02:09 EDT 2020. Contains 336441 sequences. (Running on oeis4.)