A154686 Numbers k such that k^3 + 2*k^2 + k + 1 is prime.

1, 2, 4, 5, 7, 12, 13, 20, 23, 25, 27, 28, 32, 33, 34, 35, 39, 42, 44, 47, 48, 49, 50, 54, 57, 75, 79, 82, 88, 89, 92, 95, 98, 99, 100, 103, 109, 110, 114, 117, 119, 120, 123, 132, 134, 137, 139, 147, 148, 160, 169, 172, 180, 189, 190, 193, 194, 200, 202, 203, 204, 205

Offset: 1

Author

Vincenzo Librandi, Jan 19 2009

Keywords

• nonn
• easy

Comments

One less than the entry in A111501. - R. J. Mathar, Jan 05 2011

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A111501, A162292 (associated primes).

Programs

Magma

[n: n in [0..210] | IsPrime(n^3+2*n^2+n+1)]; // Vincenzo Librandi, Sep 24 2012

Mathematica

Select[Range[0, 100], PrimeQ[#^3 + 2 #^2 + # + 1]&] (* Vincenzo Librandi, Sep 24 2012 *)

PARI

is(n)=isprime(n^3+2*n^2+n+1) \\ Charles R Greathouse IV, May 22 2017