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A217133
Numbers n such that 5^n + 8 is prime.
1
1, 95, 335, 3155, 28651, 91135
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
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
KEYWORD
nonn,more
AUTHOR
Vincenzo Librandi, Oct 01 2012
EXTENSIONS
a(5)-a(6) from Robert Price, Feb 03 2014
STATUS
approved