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It migt be true, that a Cullen number Cp is divisible by 2p-1, if p is a prime and . But there exist other Cp is divisible by 2p-1, where p is not equal to 8k-3. At last there exist n there neither prime nor of the form 8k-1, but Cn is divisble by 2n-1.
n c(n) 2n-1 8k-3 d/n ---------------------------- 1 3 1 d 2 9 3 d 3 25 5 1 d 4 65 7 n 5 161 9 n 6 385 11 d 7 897 13 2 d 8 2049 15 n 9 4609 17 n 10 10241 19 d 11 22529 21 n 12 49153 23 d
I think, this is a very weak property. -- Arbol01 18:07, 11 Feb 2005 (UTC)
At first reading, the second paragraph sounded self-contradictory to me. But I saw that the page almost all indicates alternate meanings besides the "all but finitely many" that I'm used to in number theory. I would recommend specifying which definition of "almost all" you are referring to, such as almost all Cullen numbers are composite, in the sense that the number of Cullen numbers less than x, divided by x, approaches zero as x approaches infinity.
Johnny Vogler ( talk) 21:30, 26 October 2008 (UTC)
The numerator of the number (−n)*2−n + 1 is 2n - n, the first few of them are
Numbers n such that 2n - n is prime are
The dual Cullen prime themselves are
I have removed a section called "Dual Cullen number" with the above content. It was addded today by 49.215.193.130. Reasons for removal:
PrimeHunter ( talk) 23:44, 29 May 2015 (UTC)
(−n)*2−n + 1 = (2n - n)/(2n), and the numerator of this number is 2n - n — Preceding unsigned comment added by 117.19.50.93 ( talk) 19:35, 28 April 2018 (UTC)
This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||
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It migt be true, that a Cullen number Cp is divisible by 2p-1, if p is a prime and . But there exist other Cp is divisible by 2p-1, where p is not equal to 8k-3. At last there exist n there neither prime nor of the form 8k-1, but Cn is divisble by 2n-1.
n c(n) 2n-1 8k-3 d/n ---------------------------- 1 3 1 d 2 9 3 d 3 25 5 1 d 4 65 7 n 5 161 9 n 6 385 11 d 7 897 13 2 d 8 2049 15 n 9 4609 17 n 10 10241 19 d 11 22529 21 n 12 49153 23 d
I think, this is a very weak property. -- Arbol01 18:07, 11 Feb 2005 (UTC)
At first reading, the second paragraph sounded self-contradictory to me. But I saw that the page almost all indicates alternate meanings besides the "all but finitely many" that I'm used to in number theory. I would recommend specifying which definition of "almost all" you are referring to, such as almost all Cullen numbers are composite, in the sense that the number of Cullen numbers less than x, divided by x, approaches zero as x approaches infinity.
Johnny Vogler ( talk) 21:30, 26 October 2008 (UTC)
The numerator of the number (−n)*2−n + 1 is 2n - n, the first few of them are
Numbers n such that 2n - n is prime are
The dual Cullen prime themselves are
I have removed a section called "Dual Cullen number" with the above content. It was addded today by 49.215.193.130. Reasons for removal:
PrimeHunter ( talk) 23:44, 29 May 2015 (UTC)
(−n)*2−n + 1 = (2n - n)/(2n), and the numerator of this number is 2n - n — Preceding unsigned comment added by 117.19.50.93 ( talk) 19:35, 28 April 2018 (UTC)