%I #6 Sep 08 2022 08:46:01

%S 19,79,179,499,719,1279,1619,1999,2879,3919,5119,5779,7219,8819,9679,

%T 11519,15679,19219,20479,24499,25919,28879,33619,35279,36979,40499,

%U 44179,49999,56179,71999,74419,79379,81919,84499,87119,89779

%N Primes of the form 5n^2 - 1.

%H Vincenzo Librandi, <a href="/A201783/b201783.txt">Table of n, a(n) for n = 1..5000</a>

%t Select[Table[5n^2-1,{n,0,1000}],PrimeQ]

%o (Magma) [a: n in [0..300] | IsPrime(a) where a is 5*n^2-1];

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, Dec 05 2011