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A217133 Numbers n such that 5^n + 8 is prime. 1
1, 95, 335, 3155, 28651, 91135 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Naturally these numbers are odd since (6-1)^(2n)+8 is divisible by 3. - Bruno Berselli, Oct 04 2012

a(7) > 10^5. - Robert Price, Feb 03 2014

a(7) > 5*10^5. - Tyler NeSmith, Apr 24 2022

LINKS

Table of n, a(n) for n=1..6.

MATHEMATICA

Select[Range[1, 15000, 2], PrimeQ[5^# + 8] &]

PROG

(PARI) for(n=1, 5*10^3, if(isprime(5^n+8), print1(n", ")))

CROSSREFS

Cf. A087885, A089142, A124621.

Sequence in context: A008875 A174157 A200882 * A055823 A116250 A020322

Adjacent sequences:  A217130 A217131 A217132 * A217134 A217135 A217136

KEYWORD

nonn,more

AUTHOR

Vincenzo Librandi, Oct 01 2012

EXTENSIONS

a(5)-a(6) from Robert Price, Feb 03 2014

STATUS

approved

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Last modified October 6 16:34 EDT 2022. Contains 357270 sequences. (Running on oeis4.)