[seqfan] Re: -5 is not a prime

[Ami Eldar]

To answer Marc's question:

I don't remember in what specific sequences I saw such problems, but here
is something that I have just made up:

Primes of the form k^2-40*k+369.

Using pari:
for(k=1,39,if(isprime(k^2-40*k+369),print1(k,", ")))
we will get 2, 8, 14, 26, 32, 38
and using Mathematica:
For[k = 1, k < 40, k++, If[PrimeQ[k^2-40*k+369], Print[k]]]
we will get almost the same terms, 2, 8, 14, 20, 26, 32, 38 - but there is
one extra term...

Best,
Amiram





On Sun, Jan 3, 2021 at 9:39 PM Marc LeBrun <mlb at well.com> wrote:

> > (it has led people to make mistakes in sequences)
>
> It's certainly critical to avoid errors, so I am most curious what sorts
> of mistakes these have been?
>
>  I can imagine several possibilities (eg inconsistent values, buggy code,
> etc).  It'd be nice to have specific examples to consider.
>
> Perhaps that could suggest what might be the best course of action, from
> the perspective of what's best for the OEIS?
>
>
> Rather than arguing definitions, it might be easier to simply adopt an
> editorial policy that if a technically nuanced interpretation of the word
> prime is material, that it would be a kindness to somehow mention that
> explicitly in the packaging?
>
>
> Happy 43 * 47!
>
> Warning! Prime ingredients may include eggs, milk, wheat, tree nuts, red
> dye #2, phenylalanine and values other than counting numbers greater than
> one.
>
>
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