A084898 Numbers k such that k^k*k! + 1 is prime.

1, 3, 7, 13, 23, 55, 90, 337, 2313, 8767

Offset

1,2

Comments

All terms under 500 correspond to certified primes (Primo 2.2.0 beta). a(10) > 2500. - Ryan Propper, Apr 05 2006

a(11) > 10000. - Eric Snyder, Jun 03 2022

Links

Table of n, a(n) for n=1..10.

Example

7 is in the sequence because 7^7*7! + 1 = 4150656721 is prime.

Mathematica

Do[If[PrimeQ[n^n*n!+1], Print[n]], {n, 600}]

Crossrefs

Cf. A002981, A002982.

Sequence in context: A100720 A297852 A297953 * A147380 A146606 A101302

Adjacent sequences: A084895 A084896 A084897 * A084899 A084900 A084901

Keyword

more,nonn

Author

Farideh Firoozbakht, Jul 14 2003

Extensions

a(9) from Ryan Propper, Apr 05 2006

a(10) from Eric Snyder, Jun 03 2022

Status

approved