%I #15 Oct 01 2024 18:38:19
%S 2,3,4,5,7,11,15,26,52,116,359,1547,2465
%N Numbers k such that (k+1)*k^k - 1 is prime.
%C a(14) > 15000. - _Michael S. Branicky_, Oct 01 2024
%e 15 is in the sequence because (15+1)*15^15-1 = 16*15^15-1 = 7006302246093749999, which is prime.
%t Select[Range[1000], PrimeQ[(# + 1) #^# - 1] &] (* _Vincenzo Librandi_, Oct 23 2014 *)
%o (PARI) isok(n) = isprime((n+1)*n^n-1); \\ _Michel Marcus_, Oct 23 2014
%o (Magma) [n: n in [1..1000] |IsPrime((n+1)*n^n-1)]; // _Vincenzo Librandi_, Oct 23 2014
%Y Cf. A108879.
%K more,nonn
%O 1,1
%A _Ray G. Opao_, Jun 30 2005