# [seqfan] Re: A true Mac Mahon ruler?

Neil Sloane njasloane at gmail.com
Tue Jun 25 21:55:13 CEST 2019

```Please leave the definitions of the old classic sequences alone.

Clarifying comments are welcomed, of course.

There are tens of thousands of new sequences that need attention!

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.
Email: njasloane at gmail.com

On Tue, Jun 25, 2019 at 3:35 PM M. F. Hasler <oeis at hasler.fr> wrote:

> Eric,
> I think the NAMEs of these sequences need improvement
> A2049 is called Prime numbers of measurement,
> but actually it is defined as *partial sums* of  A002048
> <http://oeis.org/A002048> = ( 1, 2, 4, 5, 8, 10, 14, 15, 16, 21, ...)
> which is also called (Segmented numbers, or) prime numbers of measurement.
> These are defined as the set of numbers generated by excluding the sums of
> two or more **consecutive* *earlier members.
> e.g., the set has 5 = 4 + 1, but 1 and 4 are not CONSECUTIVE in that
> sequence.
>
> - Maximilian
>
> On Tue, Jun 25, 2019 at 2:00 PM Éric Angelini <eric.angelini at skynet.be>
> wrote:
>
> > Hello SeqFans,
> > The first 8 terms of A002049 are:
> > 1,3,7,12,20,30,44 and 59.
> > I see that I can measure 29 in two
> > ways with this ruler (I thought only
> > one way was authorized):
> > 30-1=29
> > 59-30=29
> > I am obviously missing smthg as this
> > is an ancient seq. signed by Neil himself.
> > Anyway -- is it possible to build a
> > wooden ruler with as few as possible
> > vertical marks such that all integers
> > measures between 1 and 200 can
> > be materialized only once?
> > I guess this sort of question is as
> > old as the hat I'm wearing right now to
> > avoid the killer sun we currently have
> > in Brussels. Forgive me.
> > (and if this seq is already
> > in the OEIS, my shame will
> > be complete).
> > Best,
> > É.
> >
> >
> >
> > --
> > Seqfan Mailing list - http://list.seqfan.eu/
> >
>
>
> --
> Maximilian
>
> --
> Seqfan Mailing list - http://list.seqfan.eu/
>

```