Williams primes base 5

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Reserved! This sequence is currently reserved by: Karbon

Definition

Primes of the form [math]4 \cdot {5^n{-}1}[/math].

Primes for n

1, 3, 9, 13, 15, 25, 39, 69, 165, 171, 209, 339, 2033, 6583, 15393, 282989, 498483, 504221

Search range

695000 (2019-01-17)

History

Date Remark
2019-01-17 Checked to n=695000, found n=498483 & 504221, Karsten Bonath
2018-12-07 Checked to n=321000, found n=282989, Karsten Bonath
2007-20-12 Checked to n=200000, Geoff Reynolds
2007-07-13 Checked to n=110000, Geoff Reynolds
2006-08 Found n=15393, antiroach
1981 Checked to n=500, found n=1 ... 339, H. C. Williams

External links