A079649 Numbers k such that k! + k^2 + k + 1 is prime.

0, 3, 5, 17, 24, 314, 15783

Offset

1,2

Comments

a(8) > 17548. - J.W.L. (Jan) Eerland, Oct 06 2023

Links

Table of n, a(n) for n=1..7.

Example

0!+0^2+0+1 = 1+1 = 2 which is prime, so a(1) = 0.
1!+1^2+1+1 = 1+1+1+1 = 4, which is not prime.
2!+2^2+2+1 = 2+4+2+1 = 8, which is not prime.
3!+3^2+3+1 = 6+9+3+1 = 19, which is prime, so a(2)=3.

Mathematica

For[i = 0, i < 1000, If[PrimeQ[Factorial[i] + i^2 + i + 1] == True, Print[i]]; i++ ]
n=0; Monitor[Parallelize[While[True, If[PrimeQ[Factorial[n]+n^2+n+1], Print[n]]; n++]; n], n] (* J.W.L. (Jan) Eerland, Oct 06 2023 *)

Crossrefs

Sequence in context: A025106 A333199 A203193 * A354724 A255401 A364959

Adjacent sequences: A079646 A079647 A079648 * A079650 A079651 A079652

Keyword

nonn,more

Author

Neil Fernandez, Jan 22 2003

Extensions

a(7) from J.W.L. (Jan) Eerland, Oct 06 2023

Status

approved