Primefree sequences in the OEIS

[Alonso Del Arte]

Listing 566 is a mistake.

Any sequence of n-gonal numbers will contain no primes... unless n is
itself prime, in which case the sequence will contain exactly one
prime. On the other hand, any sequence of nth powers (for n > 1) will
contain no primes, even if n is itself prime (i.e., the second powers,
or square numbers).

Mixing up these two conditions is a mistake, but an understandable one, I think.

Alonso

On 10/21/05, Hans Havermann <pxp at rogers.com> wrote:
> >> In fact, the currently-known terms *may* contain a prime: A000566
> >> contains 7. That's as far as I bothered to look.
> >
> > Then I must be missing the whole point.  I thought that the
> > sequences were to not contain primes.
>
> Sorry. I was just illustrating that in addition to being ill-
> conceived, the idea was poorly implemented. :)
>