%I #17 Sep 08 2022 08:46:04
%S 2,11,20,21,28,31,55,57,62,84,87,97,107,109,129,147,149,157,160,170,
%T 181,189,191,207,241,247,251,274,295,297,315,327,335,349,351,355,364,
%U 365,368,379,383,410,419,423,431,436,438,466,472,506,513,527,557,571,597
%N Numbers n such that (n^17-1)/(n-1) is prime.
%H Vincenzo Librandi, <a href="/A217071/b217071.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Range[2, 1000], PrimeQ[(#^17 - 1)/(# - 1)] &] (* _T. D. Noe_, Sep 26 2012 *)
%o (Magma) [n: n in [2..1000] |IsPrime((n^17 - 1) div (n - 1))]; // _Vincenzo Librandi_, Sep 28 2012
%o (PARI) is(n)=isprime((n^17-1)/(n-1)) \\ _Charles R Greathouse IV_, Feb 17 2017
%Y Cf. A002384, A049409, A100330, A162862, A217070-A217089.
%K nonn,easy
%O 1,1
%A _Tim Johannes Ohrtmann_, Sep 26 2012
%E More terms from _T. D. Noe_, Sep 26 2012