Mathematics of Computation

ISSN 1088-6842(online) ISSN 0025-5718(print)

 

 

On the primality of $n! \pm 1$ and $2 \times 3 \times 5 \times \dotsm \times p \pm 1$


Authors: Chris K. Caldwell and Yves Gallot
Journal: Math. Comp. 71 (2002), 441-448
MSC (2000): Primary 11A41; Secondary 11N05, 11A51
Published electronically: May 11, 2001
MathSciNet review: 1863013
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Abstract:

For each prime $p$, let $p\char93 $ be the product of the primes less than or equal to $p$. We have greatly extended the range for which the primality of $n! \pm 1$ and $p\char93 \pm 1$ are known and have found two new primes of the first form ( $6380!+1, 6917!-1$) and one of the second ($42209\char93 +1$). We supply heuristic estimates on the expected number of such primes and compare these estimates to the number actually found.


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Additional Information

Chris K. Caldwell
Affiliation: Department of Mathematics and Computer Science, University of Tennessee at Martin, Martin, Tennessee 38238
Email: caldwell@utm.edu

Yves Gallot
Affiliation: Department of Mathematics and Computer Science, University of Tennessee at Martin, Martin, Tennessee 38238
Address at time of publication: 12 bis rue Perrey, 31400 Toulouse, France
Email: galloty@wanadoo.fr

DOI: http://dx.doi.org/10.1090/S0025-5718-01-01315-1
Keywords: Prime numbers, factorial primes, primality proving algorithms
Received by editor(s): March 21, 2000
Published electronically: May 11, 2001
Additional Notes: The first author would like to thank the fellow faculty members who allowed us to use their computers’ idle time over a period of months, especially David Ray and John Schommer.
Article copyright: © Copyright 2001 American Mathematical Society