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

Éric Angelini eric.angelini at skynet.be
Tue Jun 25 21:43:19 CEST 2019

```You are right, Maximilian, I saw all those seq and got confused
(there are more seq dealing with this "ruler" idea -- some of them
even worse. Anyway, I understand now the "concept" (I even bought
on JSTOR a 2-page paper from 1975 a few hours ago).
The name "perfect Golomb ruler" is what I was looking for.
Merci !
É.

> Le 25 juin 2019 à 21:34, "M. F. Hasler" <oeis at hasler.fr> a écrit :
>
>
> 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/

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