[seqfan] Re: Iteration of k -> sigma(k)-1

Hugo Pfoertner yae9911 at gmail.com
Fri Sep 22 21:53:01 CEST 2017


Neil, of course, thanks! My contribution are just a few lines of trivial
PARI code and a few hours of computer time. I will let it run over night
and see how far it goes.

Best regards
Hugo

On Fri, Sep 22, 2017 at 9:46 PM, Neil Sloane <njasloane at gmail.com> wrote:

> Hugo, that's great!  I've created A292115 for the records (under both our
> names, hope that is OK)
>
> 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, Sep 22, 2017 at 3:43 PM, Hugo Pfoertner <yae9911 at gmail.com> wrote:
>
> > I've found more records of A039655:
> > 0, 2, 5, 6, 7, 11, 13, 15, 17, 21, 23, 24, 25, 26, 29, 40, 42, 44, 45,
> 46,
> > 47, 54, 55, 56, 57, 58,
> > 60, 64, 66, 72, 74
> > This is definitely different from A073485.
> >
> > On Fri, Sep 22, 2017 at 8:53 PM, Hugo Pfoertner <yae9911 at gmail.com>
> wrote:
> >
> > > Neil, all,
> > >
> > > for A039655 an a-file of 1 million terms is available.
> > >
> > > The records of A039655 I've computed so far are
> > > 0, 2, 5, 6, 7, 11, 13, 15, 17, 21, 23, 24, 25, 26, 29, 40, 42, 44, 45,
> > 46,
> > > 47, 54, 55, 56, 57, 58,
> > >
> > > A corresponding extension of A292114 is submitted.
> > >
> > > Hugo Pfoertner
> > >
> > >
> > >
> > > On Fri, Sep 22, 2017 at 3:10 PM, Neil Sloane <njasloane at gmail.com>
> > wrote:
> > >
> > >> Dear Seq Fans,
> > >> According to Richard Guy, Erdos conjectured that the trajectory of n
> > under
> > >> that map always reaches a prime. A039654 gives the prime reached, or
> -1
> > (I
> > >> changed the escape value to make it consistent with similar
> sequences),
> > >> and A039655 gives no. of steps.
> > >> I just created A292112 and -3 for the records in A039654. They need
> > >> b-files.
> > >> The record values in A039655 appear to match A073485, but surely that
> is
> > >> just a coincidence, so could someone please compute more terms? The
> > >> positions of the records in A039655 is the new A292114.
> > >>
> > >> In other words, the records in the present b-file for A039655 are [0,
> 2,
> > >> 5,
> > >> 6, 7, 11, 13, 15, 17] - how does this continue?
> > >> The positions of the records are [2, 4, 9, 121, 301, 441, 468, 3171,
> > 8373]
> > >> which is now A292114. How does this continue, and what ARE these
> > numbers?
> > >>
> > >> A039655 could use a bigger b-file, or an a-file with 100,000 or more
> > >> terms.
> > >>
> > >> --
> > >> Seqfan Mailing list - http://list.seqfan.eu/
> > >>
> > >
> > >
> >
> > --
> > Seqfan Mailing list - http://list.seqfan.eu/
> >
>
> --
> Seqfan Mailing list - http://list.seqfan.eu/
>


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