OFFSET
1,3
COMMENTS
Next term, if it exists, is >4800. - Ryan Propper, Jan 02 2007
From Farideh Firoozbakht, Oct 21 2009: (Start)
Numbers corresponding to a(19)-a(24) are probable primes.
There is no further term up to 8300. (End)
EXAMPLE
727 = 6! + 7 is a prime but 8! + 11 is composite hence 6 is a member but 8 is not.
7 is in the sequence because 7!=5040, nextprime(7)=11 and 5040+11 is prime.
MATHEMATICA
Do[If[PrimeQ[k!+NextPrime[k]], Print[k]], {k, 0, 1525}] (* Farideh Firoozbakht, Feb 26 2004 *)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 16 2003
EXTENSIONS
More terms from Farideh Firoozbakht, Feb 26 2004
Edited by N. J. A. Sloane at the suggestion of Artur Jasinski, Apr 14 2008
a(22)-a(24) from Farideh Firoozbakht, Oct 21 2009
a(25) from Michael S. Branicky, Aug 05 2024
STATUS
approved