[seqfan] Re: A174397 and primes with negative value.

Jonathan Post jvospost3 at gmail.com
Fri Mar 19 18:27:05 CET 2010

"A prime number (or prime integer, often simply called a "prime" for
short) is a positive integer p>1 that has no positive integer divisors
other than 1 and p itself. (More concisely, a prime number p is a
positive integer having exactly one positive divisor other than

I can see that -2 is a prime in Z, as it is only divisible by itself,
the unit -1, and the positive prime 2. But that requires tweaking the
initial definition to substitute "unit" for "1."

On Fri, Mar 19, 2010 at 10:16 AM, Richard Mathar
<mathar at strw.leidenuniv.nl> wrote:
> V. Orlovsky is defending his definition in A174397 (with negative numbers,
> obviously) with a link to http://primes.utm.edu/notes/faq/negative_primes.html
> arguing that primes can be negative numbers, so the mention of absolute
> values in the definition is not needed. I cannot make friend with that idea.
> Is there a general consensus (at least within the OEIS) that primes are >=2 ?
> Richard Mathar
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