A187714 Odd numbers m divisible by 3 such that for every k >= 1, m*2^k - 1 has a divisor in the set {5, 7, 11, 13, 17, 19, 31, 37, 41, 61, 73, 109, 151, 241, 331}.

7148695169714208807, 17968583418362170239, 26363076126393718191, 57376760867272385247, 67950587841687767283, 73873959473901564111, 81055172741266754727, 96217896533288105991, 104173338506128098489

Offset: 1

Author

Arkadiusz Wesolowski, Mar 17 2011

Keywords

• nonn

Comments

Wilfrid Keller (2004, published) gave the first known example.

7148695169714208807 computed in 2017 by the author.

Conjecture: 7148695169714208807 is the smallest Riesel number that is divisible by 3. - Arkadiusz Wesolowski, May 12 2017

Links

• Chris Caldwell, The Prime Glossary, Riesel number
• Carlos Rivera, Problem 49

Crossrefs

Cf. A101036, A187716.

Extensions

Name changed and entry revised by Arkadiusz Wesolowski, May 11 2017