Cullen number

A Cullen numberMathworldPlanetmath Cm is a number of the form 2mm+1, where m is an integer. Almost all Cullen numbers are composite, and they have 2m-1 as a factor if that number is a prime of the form 8k-3 (with k a positive integer). The first few Cullen numbers are 1, 3, 9, 25, 65, 161, 385, 897, 2049, 4609 (listed in A002064 of Sloane’s OEIS). With the exception of 3, no Proth number is also a Cullen number.

Title Cullen number
Canonical name CullenNumber
Date of creation 2013-03-22 17:21:34
Last modified on 2013-03-22 17:21:34
Owner PrimeFan (13766)
Last modified by PrimeFan (13766)
Numerical id 5
Author PrimeFan (13766)
Entry type Definition
Classification msc 11A51
Related topic WoodallNumber