Difference between revisions 19413408 and 19943463 on enwiki

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Zeisel number
A '''Zeisel number''' is a [[square-free]] [[integer]] ''k'' with at least three [[prime factor]]s which fall into the pattern 

:<math>p_x = ap_{x - 1} + b</math>

(contracted; show full)

Other Carmichael numbers of that kind are: 294409, 56052361, 118901521, 172947529, 216821881, 228842209, 1299963601, 2301745249, 9624742921, ...

The name Zeisel numbers was probably introduced by Kevin Brown, who was looking for numbers that when plugged into the equation 

:<math>2^{k - 1} + k</math> 

yield [[prime number]]s. In a posting to the [[newsgroup]] sci.math on 
[[1994-02-24]], Helmut Zeisel pointed out that 1885 is one such number. Later it was discovered (by Kevin Brown?) that 1885 additionally has prime factors with the relationship described above, so a name like Brown-Zeisel Numbers might be more appropriate.

==External links==

*[http://www.research.att.com/projects/OEIS?Anum=A051015 Sloane Sequence A051015]
*[[Wikisource:Zeisel_numbers]]
*[http://mathworld.wolfram.com/ZeiselNumber.html MathWorld article]
*[http://www.mathpages.com/home/kmath015.htm MathPages article]

[[Category:Integer sequences]]

[[de:Zeisel-Zahl]]
[[fr:Nombre de Zeisel]]