David Bernier writes: > On 10/25/2013 04:06 AM, Robin Chapman wrote: > > On 24/10/2013 18:05, David Bernier wrote: > >> > >> - what's so special about Grothendieck's prime ? > > > > You mean soixante-cinq? > > No, not as far as I know. This is based purely on a story (legend?) > told about Grothendieck in Allyn Jackson's 2004 Part II article in > Notices of the AMS, "Comme appele du neant" "As If Summoned from the > Void". > > The story retold by Allyn Jackson is this: In a conversation on > mathematics, an interlocutor asks Grothendieck to please specify > a prime (say for "ell"); Grothendieck: "You mean an actual value?" > Interlocutor: yes, Grothendieck: "All right then. Let it be 57". > > 57 = 3*19 , so I guess I got it right.
That must be one of the numbers that "look prime but aren't" mentioned in the book Concrete Mathematics. The examples in the book are 91 and 161 (multiples of 7).