A055490 - OEIS

%I #32 Dec 31 2023 10:12:16

%S 5,23,719,5039,479001599,87178291199,

%T 265252859812191058636308479999999,

%U 263130836933693530167218012159999999,8683317618811886495518194401279999999

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

%C For further information see A002982, which is the main entry.

%C Also primes of the form 1*1! + 2*2! + ... + n*n!. - _Jonathan Vos Post_, Jul 21 2006

%C Prime numbers that are the difference of two factorial numbers. - _Juri-Stepan Gerasimov_, Nov 08 2010

%H T. D. Noe, <a href="/A055490/b055490.txt">Table of n, a(n) for n=1..12</a>

%F p = n!-1 for some n given in A002982.

%t Select[Range[40]!-1,PrimeQ] (* _Harvey P. Dale_, Aug 16 2012 *)

%Y Cf. A000142, A000203, A002982.

%K nonn

%O 1,1

%A _Labos Elemer_, Jun 28 2000

%E Edited by _Jon E. Schoenfield_, Jan 09 2015