Williams primes base 5
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
Search range
321000 (2018-12-07)
History
Date | Remark |
---|---|
2018-12-07 | 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 | Found n=1 ... 339, checked to n=500, H. C. Williams |