[seqfan] Re: A133579

[Neil Sloane]

Harvey, Thanks for your work on A133580 and A133058.  As for A133579, I
corrected the terms and added a companion sequence A253092.

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 Sat, Feb 14, 2015 at 11:33 AM, Harvey P. Dale <hpd at hpdale.org> wrote:

>         I checked the Mma programs for A133580 and they are still okay
> even after the offset was changed.  I recomputed the b-file to reflect the
> changed offset and the new b-file has now been uploaded.
>         I cannot generate the terms of A133579 even using Neil's revised
> definition so I suspect the revised definition is still not correct.
>         Best,
>         Harvey
>
> -----Original Message-----
> From: SeqFan [mailto:seqfan-bounces at list.seqfan.eu] On Behalf Of Neil
> Sloane
> Sent: Friday, February 13, 2015 9:22 PM
> To: Sequence Fanatics Discussion list
> Subject: [seqfan] Re: A133579
>
> A133058 needed  a similar correction (and lacks a b-file - Harvey?)
>
> 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 Fri, Feb 13, 2015 at 9:13 PM, Neil Sloane <njasloane at gmail.com> wrote:
>
> > First, about A133580: the definition was correct, and the terms were
> > correct, but the offset should have been 0.  I changed the offset and
> > added some example lines to clarify the situation.
> >
> > The b-file is now wrong, unfortunately (Harvey, could you correct
> > it?), and probably the programs also need correcting.
> >
> > Following Franklin's hint, this suggests that the correct definition
> > of A133579 should be:
> >
> > a(0)=a(1)=1; for n>1, a(n) = 3*a(n-1)  if a(n-1) and n are coprime,
> > otherwise a(n) = a(n-1)/gcd(a(n-1),n).
> >
> > This almost matches the terms, but there is a mistake at a(6), I
> > believe, - as Harvey noticed - so it needs to be recomputed. (a(6)
> > should be 1 not 9). The offset is also wrong, it should be 0, and I
> > will fix that.
> >
> > 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 Fri, Feb 13, 2015 at 8:33 PM, Frank Adams-Watters <
> > franktaw at netscape.net> wrote:
> >
> >> The definition is clearly wrong, since gcd(n,a(n-1)) always divides
> >> a(n-1).
> >>
> >> A133580 seems to be related, and may provide a clue. (BTW, the offset
> >> for
> >> A133580 is wrong; from the definition it should be 0.)
> >>
> >> Franklin T. Adams-Watters
> >>
> >>
> >> -----Original Message-----
> >> From: Harvey P. Dale <hpd at hpdale.org>
> >> To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
> >> Sent: Fri, Feb 13, 2015 6:59 pm
> >> Subject: [seqfan] A133579
> >>
> >>
> >>         I cannot figure out how to generate the terms of the above
> >> sequence from its definition.
> >>         Best,
> >>         Harvey
> >>
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> >
> >
>
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