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A217135
Numbers k such that 3^k - 8 is prime.
17
3, 4, 7, 8, 14, 20, 22, 62, 139, 254, 272, 430, 907, 1906, 2278, 2827, 3598, 6812, 15266, 20915, 26180, 26342, 27022, 48275, 65186, 69247, 86647
OFFSET
1,1
COMMENTS
a(28) > 2*10^5. - Robert Price, Sep 02 2013
MATHEMATICA
Select[Range[2, 5000], PrimeQ[3^# - 8] &]
PROG
(PARI) for(n=2, 5*10^3, if(isprime(3^n-8), print1(n", ")))
CROSSREFS
KEYWORD
nonn
AUTHOR
Vincenzo Librandi, Oct 01 2012
EXTENSIONS
a(18)-a(27) from Robert Price, Sep 02 2013
STATUS
approved