

A125881


Numbers k for which k^3+k^21 is prime.


15



2, 4, 5, 6, 9, 11, 12, 14, 19, 22, 25, 26, 27, 29, 32, 34, 36, 37, 40, 44, 47, 49, 55, 60, 62, 64, 65, 69, 70, 71, 81, 82, 84, 89, 95, 97, 106, 107, 114, 119, 121, 125, 127, 132, 139, 140, 141, 144, 147, 155, 159, 161, 165, 172, 174, 179, 184, 190, 201, 204
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OFFSET

1,1


COMMENTS

Generating polynomial belongs to the family of irreducible polynomials (or trinomials) of the form x^n+x^(n1)1.


LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Harvey P. Dale)


MATHEMATICA

Do[If[PrimeQ[x^3 + x^2  1], Print[x]], {x, 1, 100}]
Select[Range[250], PrimeQ[#^3 + #^2  1] &] (* Harvey P. Dale, Jan 20 2015 *)


PROG

(PARI) isok(n) = isprime(n^3+n^21); \\ Michel Marcus, Nov 08 2013


CROSSREFS

Cf. A045546, A125882, A125883, A125884, A125885.
Sequence in context: A050011 A030303 A047315 * A287370 A089969 A166944
Adjacent sequences: A125878 A125879 A125880 * A125882 A125883 A125884


KEYWORD

nonn


AUTHOR

Artur Jasinski, Dec 14 2006


EXTENSIONS

More terms from Michel Marcus, Nov 08 2013


STATUS

approved



