A049433 Numbers k such that k! - (k-1)! - 1 is prime.

3, 4, 6, 8, 9, 12, 28, 78, 99, 184, 286, 291, 398, 411, 600, 718, 732, 889, 1963, 2240, 2242, 2533, 8800, 11403, 18335, 20277, 21029

Offset

1,1

Comments

There is no further term up to 1400. - Farideh Firoozbakht, Jul 18 2003

a(25) > 12000. [Donovan Johnson, Dec 18 2009]

Links

Table of n, a(n) for n=1..27.

Index entries for sequences related to factorial numbers

Formula

a(n) = A090704(n) + 1 = n*n! + 1 = ((n+1)-1)*n! + 1 = (n+1)! - n! + 1 .

Example

6 is a term since 6! - (6-1)! - 1 = 599 is prime.

Crossrefs

Cf. A049432, A049985, A090704.

Cf. A001272, A002981, A002982.

Sequence in context: A059267 A362670 A355200 * A250984 A383649 A298809

Adjacent sequences: A049430 A049431 A049432 * A049434 A049435 A049436

Keyword

nonn

Author

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

Extensions

More terms from Farideh Firoozbakht, Jul 18 2003

Corrected offset, edited definition and a(19)-a(24) from Donovan Johnson, Dec 18 2009

a(25)-a(27) from Michael S. Branicky, Jun 13 2025

Status

approved