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A216591
Numbers k such that 8^k + k^8 - 1 is prime.
1
10, 38, 428, 824, 3902, 4712, 5596, 29572
OFFSET
1,1
COMMENTS
a(9) > 10^5. Robert Price, Feb 25 2014
MATHEMATICA
Select[Range[0, 4000], PrimeQ[8^# + #^8 - 1] &]
PROG
(PARI) is(n)=ispseudoprime(8^n+n^8-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Vincenzo Librandi, Sep 09 2012
EXTENSIONS
a(6)-a(8) from Robert Price, Feb 25 2014
STATUS
approved