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Numbers k such that 10^k + k^10 - 1 is prime.
1

%I #16 Jul 12 2018 11:34:20

%S 2,8,1592,2380

%N Numbers k such that 10^k + k^10 - 1 is prime.

%C Next term > 10^4.

%C a(5) > 10^5. - _Robert Price_, Oct 08 2015

%t Select[Range[0, 5000], PrimeQ[10^# + #^10 - 1] &]

%o (PARI) is(n)=ispseudoprime(10^n+n^10-1) \\ _Charles R Greathouse IV_, Jun 13 2017

%Y Cf. A100357, A215434-A215446, A216375.

%K nonn,hard,more

%O 1,1

%A _Vincenzo Librandi_, Sep 11 2012