Two contradictory conjectures concerning Carmichael numbers

Erdos conjectured that there are x1-o(1) Carmichael numbers up to x, whereas Shanks was skeptical as to whether one might even find an x up to which there are more than x Carmichael numbers. Alford, Granville and Pomerance showed that there are more than x2/7 Carmichael numbers up to x, and gave arguments which even convinced Shanks (in person-to-person discussions) that Erdos must be correct. Nonetheless, Shanks's skepticism stemmed from an appropriate analysis of the data available to him (and his reasoning is still borne out by Pinch's extended new data), and so we herein derive conjectures that are consistent with Shanks's observations, while fitting in with the viewpoint of Erdos and the results of Alford, Granville and Pomerance.

• Type: Journal
• Year: 2002
• Where: MOC
• Authors: Andrew Granville, Carl Pomerance
• Keywords: Carmichael Numbers, MOC 2002, Person-to-person Discussions, Shanks