The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A055490 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A055490

Factorial primes: primes of the form n! - 1.
(history; published version)

#32 by Joerg Arndt at Sun Dec 31 10:12:16 EST 2023

STATUS

editing

approved

#31 by Joerg Arndt at Sun Dec 31 10:11:52 EST 2023

COMMENTS

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

MATHEMATICA

lst={}; Do[p=n!-1; If[PrimeQ[p], AppendTo[lst, p]], {n, 0, 5*5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Jan 27 2009 *)

#30 by Paolo P. Lava at Sun Dec 31 09:47:02 EST 2023

COMMENTS

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.]

STATUS

approved

editing

#29 by Danny Rorabaugh at Wed Nov 25 22:41:15 EST 2015

STATUS

proposed

approved

#28 by Jon E. Schoenfield at Wed Nov 25 22:15:44 EST 2015

STATUS

editing

proposed

#27 by Jon E. Schoenfield at Wed Nov 25 22:15:38 EST 2015

CROSSREFS

Cf. A002982, A000203, A000142, A000203, A002982.

#26 by Jon E. Schoenfield at Wed Nov 25 22:15:13 EST 2015

NAME

Factorial primes: primes of the form n! - 1.

COMMENTS

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.]

STATUS

approved

editing

#25 by Michel Marcus at Sat Jan 10 04:05:27 EST 2015

STATUS

reviewed

approved

#24 by Joerg Arndt at Sat Jan 10 04:01:52 EST 2015

STATUS

proposed

reviewed

#23 by Jon E. Schoenfield at Fri Jan 09 19:57:26 EST 2015

STATUS

editing

proposed