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Numbers n such that n!-(n-1)!-1 is prime.
5

%I #9 Mar 31 2012 14:40:08

%S 3,4,6,8,9,12,28,78,99,184,286,291,398,411,600,718,732,889,1963,2240,

%T 2242,2533,8800,11403

%N Numbers n such that n!-(n-1)!-1 is prime.

%C There is no further term up to 1400. - _Farideh Firoozbakht_, Jul 18 2003

%C a(25) > 12000. [From _Donovan Johnson_, Dec 18 2009]

%H <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a>

%e 6!-(6-1)!-1 = 599 is prime.

%Y Cf. A049432, A049985.

%Y Cf. A001272, A002981, A002982.

%K nonn

%O 1,1

%A Paul Jobling (paul.jobling(AT)whitecross.com)

%E More terms from _Farideh Firoozbakht_, Jul 18 2003

%E Corrected offset, edited definition and a(19)-a(24) from _Donovan Johnson_, Dec 18 2009