%I #15 Sep 08 2022 08:46:04
%S 5,17,19,55,62,75,89,98,99,132,172,186,197,220,268,278,279,288,439,
%T 443,496,579,583,587,742,777,825,911,966,1003,1029,1155,1202,1267,
%U 1377,1461,1472,1473,1530,1562,1634,1682,1705,1783,1848,1852,1885,1900,1943,1957
%N Numbers n such that (n^47-1)/(n-1) is prime.
%H Vincenzo Librandi, <a href="/A217079/b217079.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Range[2, 2000], PrimeQ[(#^47 - 1)/(# - 1)] &] (* _T. D. Noe_, Sep 26 2012 *)
%o (Magma) [n: n in [2..2000] |IsPrime((n^47 - 1) div (n - 1))]; // _Vincenzo Librandi_, Sep 28 2012
%o (PARI) is(n)=isprime((n^47-1)/(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