A051856 Numbers n such that (n!)^2+n!+1 is prime.

0, 1, 2, 3, 4, 6, 76, 2837, 6001, 7076

Offset

1,3

References

H. Dubner, Factorial and primorial primes, J. Rec. Math., 19 (No. 3) (1987)

Links

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

C. K. Caldwell, The Prime Pages

C. Nash, Prime Form [broken link]

M. Oakes, Re: Gaussian primorial and factorial primes, Primeform, Dec 21 2010

Mike Oakes, Andrew Walker, David Broadhurst, Gaussian primorial and factorial primes, digest of 7 messages in primeform Yahoo group, Dec 20 - Dec 21, 2010.

Example

6 is in the sequence because (6!)^2+6!+1=519121 is prime.

Mathematica

Do[If[PrimeQ[n!^2+n!+1], Print[n]], {n, 600}] (* Farideh Firoozbakht, Jul 12 2003 *)

Crossrefs

Cf. A002981, A002982, A046029.

Sequence in context: A033179 A067244 A084811 * A135236 A029962 A259388

Adjacent sequences: A051853 A051854 A051855 * A051857 A051858 A051859

Keyword

nonn,hard,more

Author

Andrew Walker (ajw01(AT)uow.edu.au), Dec 13 1999

Extensions

Edited by R. J. Mathar, Aug 08 2008

a(8)-a(10) from Serge Batalov, Nov 24 2011

Status

approved