cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

Original entry on oeis.org

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

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Author

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

Keywords

Comments

There is no further term up to 1400. - Farideh Firoozbakht, Jul 18 2003
a(25) > 12000. [Donovan Johnson, Dec 18 2009]

Examples

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

Links

Crossrefs

Cf. A049432, A049985, A090704.
Cf. A001272, A002981, A002982.

Formula

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

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
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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