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%I #18 Aug 11 2024 13:55:47
%S 2,3,5,21,75
%N Numbers k such that k^k - (k-1)^2 is prime.
%C a(6), if it exists, is greater than 9000. - _Ryan Propper_, May 17 2006
%C a(6), if it exists, is greater than 20000. - _Michael S. Branicky_, Aug 11 2024
%t Select[Range[80],PrimeQ[#^#-(#-1)^2]&] (* _Harvey P. Dale_, Aug 15 2013 *)
%o (PARI) is(n)=ispseudoprime(n^n-(n-1)^2) \\ _Charles R Greathouse IV_, Jun 13 2017
%K more,nonn
%O 1,1
%A _Jason Earls_, May 23 2004