Williams primes of the form 2•3n-1

Reserved! This sequence is currently reserved by: Borys Jaworski

Last update: 2019-04-14

Reserved! This sequence is currently reserved by: Borys Jaworski

Current data

Base : 3 Count : 37 Max n : 1,840,000 Date : 2019-03-01 Reserved : Borys JaworskiBorys Jaworski/Reserved

1, 2, 3, 7, 8, 12, 20, 23, 27, 35, 56, 62, 68, 131, 222, 384, 387, 579, 644, 1772, 3751, 5270, 6335, 8544, 9204, 12312, 18806, 21114, 49340, 75551, 90012, 128295, 143552, 147488, 1010743, 1063844, 1360104

History

• 2015-07-31: Found n = 1360104, Borys Jaworski, Riesel Prime Search
• 2012-02-12: Found n = 1063844, Borys Jaworski, Riesel Prime Search
• 2011-09-01: Found n = 1010743, Borys Jaworski, Riesel Prime Search
• 2009-04-12: Checked n to 570000, David Broadhurst
• 2009-03-09: Checked n = 189000 to 400000, David Broadhurst
• 2004-08-15: Found n = 147488, Ingo Buechel, Wilfrid Keller
• 2004-08-12: Found n = 143552, Ingo Buechel, Wilfrid Keller
• 2003-06-20: Found n = 128295, Ingo Buechel, Wilfrid Keller
• 2001-09-28: Found n = 90012, Wilfrid Keller
• 2001-08-12: Found n = 75551, Wilfrid Keller
• 2001-06-30: Found n = 49340, Wilfrid Keller
• 1972: Found n = 1 ... 222, H.C.Williams, C.R.Zarnke

External links

• Active search, last update post #72
• The sequence A003307 in OEIS
• H.C.Williams, C.R.Zarnke: "Some prime numbers of the forms 2A3^n+1 and 2A3^n-1" Math. Comp. 26 (1972), 995-998