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%I #18 Oct 14 2023 23:31:27
%S 2,3,5,7,167
%N Numbers k such that A055869(k) = (k+1)^k - k^k is prime.
%C The next term is > 5000.
%e a(2) = 3 because (3+1)^3 - 3^3 = 4^3 - 3^3 = 64 - 27 = 37 is prime.
%t Select[Range[300], PrimeQ[(#+1)^#-#^#]&] (* _Vladimir Joseph Stephan Orlovsky_, Mar 03 2011 *)
%o (Magma) [n: n in [0..190]| IsPrime((n+1)^n -n^n)]; // _Vincenzo Librandi_, Jun 22 2014
%o (PARI) isok(k) = ispseudoprime((k+1)^k - k^k); \\ _Jinyuan Wang_, Mar 19 2020
%Y Cf. A055869 ((n+1)^n-n^n), A085682 (k^k-(k-1)^k is prime).
%K nonn,hard,more
%O 1,1
%A _Hugo Pfoertner_, Sep 14 2004
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