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Re: 1 as a prime number
Posted:
Dec 8, 1997 7:22 PM


At 4:00 PM 0500 12/8/97, John Conway wrote: >On Mon, 8 Dec 1997, mark snyder wrote: > >> At 9:58 PM 0200 12/7/97, Julio Gonzalez Cabillon wrote: >> >At 07:47 PM 05/12/1997 GMT, Mark Snyder wrote: >> >>I have heard that until about 1800, 1 was considered to be a prime number. >> >>Is this correct? >> > >> >Not quite! JGC >> >> So what *is* correct? >> >> >> mark snyder >> > I answered this at some length a few days ago. The tradition >before this century (dating back to Euclid's Elements) was indeed >to count 1 as a prime, and even Lehmer's 1914 list of prime numbers to >10 million does so. But the many inconveniences it causes have >led people this century to put it into a new category, and call >it a "unit" rather than a prime. > > John Conway
And I appreciate the time you took to answer my question. Perhaps I was not clear on what the question was. I know why it is undesirable to consider 1 as a prime number, and it is interesting that it was considered prime by Lehmer as late as 1914. But my question was: when did it became gradually accepted that we should not consider 1 as a prime number? A colleague of mine had said that he read somewhere (but didn't remember where) that 1800 was some kind of watershed in this regard, and what I was hoping for was some reference where I might read more about the history of this, hence the post to the math history list. Evidently my colleague was off by 100 years, but I would still be interested in any references.
And my comment about the "big meeting" was my (evidently feeble) attempt at jocularity...
mark snyder



