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 A055490 Factorial primes: primes of the form n! - 1. 11
 5, 23, 719, 5039, 479001599, 87178291199, 265252859812191058636308479999999, 263130836933693530167218012159999999, 8683317618811886495518194401279999999 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS For further information see A002982, which is the main entry. Also primes of the form (n!-1) mod (n-1)!, with n>=1. - Paolo P. Lava & Giorgio Balzarotti, Mar 14 2007. [This follows because every number of the form (n!-1) mod (n-1)! is 1 less than a factorial.] Also primes of the form 1*1! + 2*2! + ... + n*n!. Example: 1*1! + 2*2! + 3*3! + 4*4! + 5*5! + 6*6! + 7*7! + 8*8! + 9*9! + 10*10! + 11*11! + 12*12! + 13*13! = 87178291199 is prime. - Jonathan Vos Post, Jul 21 2006 Prime numbers that are the difference of two factorial numbers. - Juri-Stepan Gerasimov, Nov 08 2010 LINKS T. D. Noe, Table of n, a(n) for n=1..12 FORMULA p = n!-1 for some n given in A002982. MATHEMATICA lst={}; Do[p=n!-1; If[PrimeQ[p], AppendTo[lst, p]], {n, 0, 5*5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Jan 27 2009 *) Select[Range[40]!-1, PrimeQ] (* Harvey P. Dale, Aug 16 2012 *) CROSSREFS Cf. A000142, A000203, A002982. Sequence in context: A080990 A172036 A003487 * A261935 A299360 A002811 Adjacent sequences:  A055487 A055488 A055489 * A055491 A055492 A055493 KEYWORD nonn AUTHOR Labos Elemer, Jun 28 2000 EXTENSIONS Edited by Jon E. Schoenfield, Jan 09 2015 STATUS approved

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Last modified December 13 15:03 EST 2018. Contains 318086 sequences. (Running on oeis4.)