

A051856


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


6




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



