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%I #23 Sep 08 2022 08:46:19
%S 2,6,40,56,954
%N Numbers k such that k^k*prime(k) - 1 is prime.
%C a(6) > 22000. - _Giovanni Resta_, Jun 12 2017
%e a(1) = 2 because 3*2^2-1 = 11 a prime.
%e a(2) = 6 because 13*6^6-1 = 606527 a prime.
%t Select[Range[1000], PrimeQ[Prime[#] #^# - 1] &]
%o (Magma) [n: n in [1..1000] | IsPrime(NthPrime(n)*n^n-1)];
%Y Cf. A086173.
%K nonn,more
%O 1,1
%A _Vincenzo Librandi_, Jun 10 2017
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