# [seqfan] Re: Recaman's transform of the odd numbers

Neil Sloane njasloane at gmail.com
Tue Mar 6 20:49:20 CET 2012

```Charles is correct. You can get duplicates when you add.
That has always been part of the definition of the Recaman sequence
Neil

On Tue, Mar 6, 2012 at 1:56 PM, Charles Greathouse <
charles.greathouse at case.edu> wrote:

> As I understand it, you subtract if the result is positive and not
> already in the sequence, but otherwise you add and put the result in
> the sequence, even if it's already present.
>
> Charles Greathouse
> Analyst/Programmer
> Case Western Reserve University
>
> On Tue, Mar 6, 2012 at 12:44 PM, Eric Angelini <Eric.Angelini at kntv.be>
> wrote:
> > Hello SeqFans,
> > I'm having troubles with https://oeis.org/A128204
> >
> > 0, 1, 4, 9, 2, 11, 22, 35, 20, 3, 22, 43, 66, 41, 14, 43, ...
> > I see two times "22" and two times "43" here. Is it allowed?
> >
> > Shouldn't the sequence start:
> >
> > 0, 1, 4, 9, 2, 11, 22, 35, 20, 37, ... with a new definition?
> > (like: erase the last term leading to a contradiction and try
> > adding instead of subtracting? Such a term would be "3", in
> > the above sequence).
> >
> > ----------
> >
> > This new definition would be useful to compute a Recaman's
> > variation I don't see in the database -- the "Recaman's
> > transform of the even numbers":
> >
> > 1 3 7 13 5  15  27  41  25  43  23  45  21  47  19  49 (and not 11)
> >  2 4 6  8 10  12  14  16  18  20  22  24  26  28  30  32 ...
> >
> > Best,
> > É.
> >
> >
> > _______________________________________________
> >
> > Seqfan Mailing list - http://list.seqfan.eu/
>
> _______________________________________________
>
> Seqfan Mailing list - http://list.seqfan.eu/
>

--
Dear Friends, I will soon be retiring from AT&T. New coordinates:

Neil J. A. Sloane, President, OEIS Foundation
11 South Adelaide Avenue, Highland Park, NJ 08904, USA