A125881 - OEIS

%I #16 Mar 18 2020 07:29:32

%S 2,4,5,6,9,11,12,14,19,22,25,26,27,29,32,34,36,37,40,44,47,49,55,60,

%T 62,64,65,69,70,71,81,82,84,89,95,97,106,107,114,119,121,125,127,132,

%U 139,140,141,144,147,155,159,161,165,172,174,179,184,190,201,204

%N Numbers k for which k^3+k^2-1 is prime.

%C Generating polynomial belongs to the family of irreducible polynomials (or trinomials) of the form x^n+x^(n-1)-1.

%H Amiram Eldar, <a href="/A125881/b125881.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Harvey P. Dale)

%t Do[If[PrimeQ[x^3 + x^2 - 1], Print[x]], {x, 1, 100}]

%t Select[Range[250], PrimeQ[#^3 + #^2 - 1] &] (* _Harvey P. Dale_, Jan 20 2015 *)

%o (PARI) isok(n) = isprime(n^3+n^2-1); \\ _Michel Marcus_, Nov 08 2013

%Y Cf. A045546, A125882, A125883, A125884, A125885.

%K nonn

%O 1,1

%A _Artur Jasinski_, Dec 14 2006

%E More terms from _Michel Marcus_, Nov 08 2013