# A064539 All...are divisible by 3 but why?

zak seidov zakseidov at yahoo.com
Fri Jun 24 11:21:18 CEST 2005

```Dear Hugo,
seqfans,

the (one) point is that
other day Neil explained me
that "base" means that
SEQ is not so much interesting for OEIS.

i'm afraid that i don't yet understand
the "real" meaning of this base keyword "base"...
silly(?) Q:
is any number that is prime in base 10
is prime in other bases as well?

the more(?) interesting Q is:
are really cases n=1 and 28
the only two(?) ones(??)
making 3^(2n)+(2n)^3 prime?
see A109215 (pending, and, sorry, again "base"),
thanks, zak

%I A109215
17,5,3,11,11,3,677,17,3,83,23,3,5,29,3,1049,23,3,307
<...>
%N A109215 Smallest factor of 3^(2n)+(2n)^3.
%C A109215 For n=1,28 we have the only two(?) primes
of the form
3^(2n)+(2n)^3: 17 and 523347633027360537213687137.
Cases n=3*m are trivial and may be omitted.
<...>
%K A109215 ,base,nice,nonn,

--- "Pfoertner, Hugo" wrote:

> [...]
>
>
> %N A109216 Smallest factor of 2^(2n+1)+(2n+1)^2.
> [...]
> %K A109216 ,base,nice,nonn,

> --------
>
> Recently we had a discussion on the use of the
> "base" keyword. In my opinion
> the sequence above is an example where "base" is
> totally inappropriate,
> because the result has nothing to do with the
> respresentation of the numbers
> in a certain base-x system.
>
> Hugo
>

__________________________________
Yahoo! Mail
Stay connected, organized, and protected. Take the tour:
http://tour.mail.yahoo.com/mailtour.html

```