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A238011
Numbers n such that (2n)! - n! - 1 is prime.
1
5, 7, 8, 15, 103, 179, 473, 2054, 3595, 4039
OFFSET
1,1
COMMENTS
No more terms up to 5000. The first six terms are as previously stated in A118813. All terms found and primes proved by OpenPFGW.
LINKS
The OpenPFGW Project, OpenPFGW
EXAMPLE
5 is a term because (2*5)! - 5! - 1 = 3628679 is prime.
4039 is a term because (2*4039)! - 4039! - 1 is prime (28058 digits).
CROSSREFS
Cf. A118813 (corresponding primes), A237443, A118812.
Sequence in context: A288151 A242408 A171952 * A140237 A032683 A182005
KEYWORD
nonn,hard,more
AUTHOR
Rick L. Shepherd, Feb 16 2014
STATUS
approved