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%I #15 Apr 01 2023 23:16:03
%S 3,5,6,9,15,87,2323
%N Numbers k such that k^(k + 1) + k - 1 is prime.
%C a(7) > 2000.
%C a(8) > 5000. - _Daniel Suteu_, Jul 25 2019
%C a(8) > 10000. - _Michael S. Branicky_, Apr 01 2023
%o (PARI) for(n=1,100,my(x=n^(n+1)+n-1);if(isprime(x),print1(n,", ")))
%Y Cf. A155499, A268987.
%K nonn,more,hard
%O 1,1
%A _Hugo Pfoertner_, Jul 23 2019
%E a(7) from _Daniel Suteu_, Jul 25 2019
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