[seqfan] Re: A030287 et al minor inconsistency

[Ray Chandler]

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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