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 A215444 Numbers k such that 7^k + k^7 + 1 is prime. 3
 0, 3, 5, 15, 375, 98003 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(6) > 8000. - Joerg Arndt, Sep 29 2012 a(7) > 2*10^5. - Robert Price, Jun 15 2014 LINKS MATHEMATICA Select[Range[0, 5000], PrimeQ[7^# + #^7 + 1] &] PROG (MAGMA) [n: n in [0..400] | IsPrime(7^n + n^7 + 1)] (PARI) is(n)=ispseudoprime(7^n+n^7+1) \\ Charles R Greathouse IV, Jun 06 2017 CROSSREFS Cf. A100357, A215441, A216423, A215442, A243934. Sequence in context: A292339 A175138 A248795 * A006593 A115724 A039782 Adjacent sequences:  A215441 A215442 A215443 * A215445 A215446 A215447 KEYWORD nonn,hard,more AUTHOR Vincenzo Librandi, Sep 06 2012 EXTENSIONS a(6) from Robert Price, May 24 2014 STATUS approved

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Last modified December 12 13:52 EST 2018. Contains 318063 sequences. (Running on oeis4.)