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Numbers n such that n^4 - n^2 - 1 is prime.
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%I #10 Aug 29 2021 11:29:59

%S 2,3,4,5,6,7,11,14,17,18,19,23,25,27,32,36,41,43,54,60,65,69,72,77,80,

%T 82,83,87,88,92,93,98,110,117,121,122,126,127,135,136,138,149,150,155,

%U 157,159,168,170,172,173,176,179,183,188,198

%N Numbers n such that n^4 - n^2 - 1 is prime.

%e for n=2, a(2) = 3 and 3^4 - 3^2 - 1 = 71 is prime.

%t lst={}; Do[If[PrimeQ[n^4-n^2-1], AppendTo[lst, n]], {n, 400}];lst

%t Select[Range[200],PrimeQ[#^4-#^2-1]&] (* _Harvey P. Dale_, Aug 29 2021 *)

%o (PARI) is(n)=isprime(n^4-n^2-1) \\ _Charles R Greathouse IV_, Jun 13 2017

%K nonn,easy

%O 1,1

%A _Michel Lagneau_, Dec 01 2010