Recent discussions on suitable sequences and base

[Olivier Gerard]

Dear Members,

Let me address a few points of current interest.
Please, do not comment by replying to the list.
I welcome comments sent to my personal address.

Olivier



NETIQUETTE
Please remember to edit the excerpts of previous
posts you quote. Just appending 2 lines of comment
to a hundred lines of another member is not acceptable.
And small, concise messages are *strongly preferred*.
(This is not a matter of individual liberty
worth dying for but the necessary respect of other readers.
Anyway, I am a local despot.)

If you feel passionate about a subject, have a break,
just consider the long view for a few seconds and reread
your post.

Also, several messages of the past week could have been sent
directly to Neil or privately.

With the steady growth of the seqfan readership, we certainly
need a FAQ and a rewrite of the welcome message.
An effort in this direction was started several times.
I welcome suggestions (please directly to me, not on the list).



BASE SEQUENCES
There are interesting 'base' sequences, and
not only binary ones.

One should note that the base keyword is sometimes
ambiguous. It does not reflect the depth of the
dependency between the sequence and one or several
counting bases.

Even constraints inspired by certain base representations
or formulated in terms of digits instead of the global
value can lead to 'basic' and profound mathematics.
The classical examples are divisibility properties but
they are many others.  I rather like our member Jeffrey Shallit's
views about this.
Challenging mathematical questions (proofs, approximations,
computational efficiency) can arise and are not to be
easily dismissed because of a 'base' or subjective
recreational character.

Some mathematical problems are naturally expressed in other bases
than 10 and the necessary standardization of the OEIS
makes some sequences artificially base-dependent.

Anyway if you don't want to get 'base' sequences when you search
for something, you can use the boolean syntax of the new
interface:

1,2,3,4,5,6   will give you about 2000 results
1,2,3,4,5,6 -keyword:base  will give you about half as much.


TRIVIA:
- The OEIS was created and is currently edited by Neil Sloane.
My own experience is that he has a broader view of (and a
keener interest in) integer sequences and their pervasiveness
in mathematics and other disciplines than most individual
contributors of this database. More than thirty years after
the H.I.S., he is still hungry for interesting new material.
Every time he has objected to something in the sequences
I used to submit to the OEIS, he was right, and I had
the opportunity to learn something.

- I almost never reject a seqfan subscription
(except for administrative regulations imposed on me about
suitable email addresses.)
In more than eight years, we had only one exclusion, and 
only after a lengthy flame war which disgusted at least
ten subscribers.