[seqfan] Re: A030287 et al minor inconsistency

[Neil Sloane]

I agree also

Best regards
Neil

Neil J. A. Sloane, President, OEIS Foundation.
11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.
Phone: 732 828 6098; home page: http://NeilSloane.com
Email: njasloane at gmail.com


On Wed, Nov 8, 2017 at 5:49 PM, Ray Chandler <rayjchandler at sbcglobal.net>
wrote:

> David,
> I agree with MFH's reasoning as well.  It was not clear from the
> descriptions that they were recursive at first glance.
> Ray
>
> > -----Original Message-----
> > From: SeqFan [mailto:seqfan-bounces at list.seqfan.eu] On Behalf Of David
> > Wilson
> > Sent: Wednesday, November 8, 2017 4:38 PM
> > To: 'Sequence Fanatics Discussion list' <seqfan at list.seqfan.eu>
> > Subject: [seqfan] Re: A030287 et al minor inconsistency
> >
> > I agree with all of MFH’s arguments that we should have a(0) = 0 in these
> > sequences.
> >
> > This convention makes it easy to include or exclude the initial 0 by
> choosing
> > staring index 0 or 1.
> >
> > Having programmed both older FORTRAN (1-based arrays) and C/C++ (0-
> > based arrays), I am well-acquainted with the joys of 0-based indexing.
> >
> > However, I think NJAS is a romantic who likes to index starting at 1.
> >
> >
> >
> > From: maximilian at hasler.fr [mailto:maximilian at hasler.fr] On Behalf Of
> M. F.
> > Hasler
> > Sent: Wednesday, November 08, 2017 1:44 PM
> > To: Ray Chandler
> > Cc: Sequence Fanatics Discussion list; David Wilson
> > Subject: Re: [seqfan] Re: A030287 et al minor inconsistency
> >
> >
> >
> >
> >
> >
> >
> > On Wed, Nov 8, 2017 at 3:31 AM, Ray Chandler
> > <rayjchandler at sbcglobal.net> wrote:
> >
> > A030287-A030290 are simply lists and should have offset 1.
> >
> >
> >
> > That might be argued about for
> >
> > A030287 = Digits of a(n)^2 do not appear in a(n-1)^2.
> >
> >
> >
> > This definition isn't complete without specifying the initial term,
> >
> > and should also say "least number > a(n-1) such that...",
> >
> > since else you could take a smaller number
> >
> > [possibly the smallest unused one, which would perfectly make sense,
> >
> > the corresponding sequence without squares already exists:
> >
> > A067581 a(n) = smallest integer not yet in the sequence with no digits in
> > common with a(n-1), a(0)=0.
> >
> > ].
> >
> >
> >
> > So, rather than a list, it is a recurrent sequence a(n) = f( a(n-1) ).
> >
> > And it is not unnatural that the initial term has index 0.
> >
> > as is the case for most recurrent sequences.
> >
> >
> >
> > The fact that this implies a(n) = n for n = 0..7 is another motivation.
> >
> > Another motivation is the fact that restriction to n=1..oo gives you the
> >
> > "...positive integer..." version, as compared to the current "nonnegative
> > integer" version.
> >
> >
> >
> > - Maximilian
> >
> > on behalf of the Committee for the defense of 0-indexed sequences ;-)
> >
> >
> >
> >
> >
> > > -----Original Message-----
> > > From: SeqFan [mailto:seqfan-bounces at list.seqfan.eu] On Behalf Of David
> > > Wilson
> > > Sent: Tuesday, November 7, 2017 10:39 PM
> > > To: 'Sequence Fanatics Discussion list' <seqfan at list.seqfan.eu>
> > > Subject: [seqfan] A030287 et al minor inconsistency
> > >
> > > I'm planning on bringing some consistency to A030287 through A030290,
> > > and to extend their b-files.
> > > A030287 and A030288 start with a(0) =0, A03028 9 and A030290 with a(1)
> > > = 0, I think all should have the same start index, I prefer 0, what
> think ye?
> > > It would be nice to agree on indexing before I update any b-files.
> > >
> > > We also have the weird
> > >
> > > A030287(n)^2 = A030288(n)  (square elements to get the next sequence)
> > > A030290(n)^3 = A030289(n)  (cube elements to get the previous
> > > sequence)
> >
> >
> > --
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>
>
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