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A088054
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Factorial primes: primes which are within 1 of a factorial number.
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3
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2, 3, 5, 7, 23, 719, 5039, 39916801, 479001599, 87178291199, 10888869450418352160768000001, 265252859812191058636308479999999, 263130836933693530167218012159999999, 8683317618811886495518194401279999999
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OFFSET
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1,1
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COMMENTS
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Conjecture: 3 is the intersection of A002981 and A002982).
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REFERENCES
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R. Mestrovic, Euclid's theorem on the infinitude of primes: a historical survey of its proofs (300 BC--2012) and another new proof, Arxiv preprint arXiv:1202.3670, 2012 - From N. J. A. Sloane, Jun 13 2012
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LINKS
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Table of n, a(n) for n=1..14.
Wikipedia, Factorial prime.
C. Caldwell's The Top Twenty, Factorial Primes.
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EXAMPLE
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3!+1=7; 7!-1=5039
39916801 is a term because 11!+1 is prime.
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MATHEMATICA
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t = {}; Do[ If[PrimeQ[n! - 1], AppendTo[t, n! - 1]]; If[PrimeQ[n! + 1], AppendTo[t, n! + 1]], {n, 50}]; t (* Robert G. Wilson v *)
Union[Select[Range[50]!-1, PrimeQ], Select[Range[50]!+1, PrimeQ]] (Noe)
fp[n_] := Module[{nf=n!}, Select[{nf-1, nf+1}, PrimeQ]]; Flatten[Table[fp[i], {i, 50}]] [From Harvey P. Dale, Dec. 18, 2010]
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CROSSREFS
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Cf. A000142, A002981, A002982.
Union of A055490 and A088332.
Sequence in context: A062088 A070029 A110094 * A085907 A024777 A002957
Adjacent sequences: A088051 A088052 A088053 * A088055 A088056 A088057
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KEYWORD
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easy,nice,nonn
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AUTHOR
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Christopher M. Tomaszewski (cmt1288(AT)comcast.net), Nov 02 2003
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EXTENSIONS
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Corrected by Paul Muljadi, Oct 11 2005
More terms from Robert G. Wilson v and T. D. Noe, Oct 12 2005
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STATUS
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approved
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