VOOZH about

URL: https://oeis.org/A051856

⇱ A051856 - OEIS

login
A051856
Numbers k such that (k!)^2 + k! + 1 is prime.
6
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
C. K. Caldwell, The Prime Pages
C. Nash, Prime Form [broken link]
M. Oakes, Re: Gaussian primorial and factorial primes, Primeform, Dec 21 2010 [broken link]
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
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