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A051857
Numbers n such that (n!)^2-n!+1 is prime.
0
2, 3, 5, 7, 38, 2319, 2996, 3321, 3892
OFFSET
1,1
COMMENTS
a(1)-a(9) are verified primes using BLS option in pfgw. - Robert Price, Aug 24 2014
a(10) > 15000. - Robert Price, Aug 24 2014
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
Mike Oakes, Andrew Walker, David Broadhurst, Gaussian primorial and factorial primes, digest of 7 messages in primeform Yahoo group, Dec 20 - Dec 21, 2010.
PROG
(PARI) isok(n) = isprime((n!)^2-n!+1); \\ Michel Marcus, Aug 26 2013
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Andrew Walker (ajw01(AT)uow.edu.au), Dec 13 1999
EXTENSIONS
a(7)-a(9) from Robert Price, Aug 24 2014
STATUS
approved