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Numbers k such that k^k - 10 is a prime.
2

%I #19 Sep 02 2024 16:28:20

%S 3,9,27,249

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

%C a(5), if it exists, is greater than 5000. - _Vaclav Kotesovec_, Mar 25 2018

%C a(5), if it exists, is greater than 25000. - _Michael S. Branicky_, Sep 02 2024

%t Select[Range[1000], PrimeQ[#^# - 10] &] (* _Vaclav Kotesovec_, Mar 25 2018 *)

%o (PARI) isok(k) = ispseudoprime(k^k - 10); \\ _Altug Alkan_, Mar 17 2018

%Y Numbers k such that k^k + b is a prime: this sequence (b=-10), A300976 (b=-5), A100408 (b=-2), A100407 (b=2), A166852 (b=3), A100837 (b=4), A100838 (b=7), A300292 (b=9), A100839 (b=10), A173974 (b=43).

%K nonn,hard,more

%O 1,1

%A _Seiichi Manyama_, Mar 17 2018