Thanks very much, Tomas and Kerry -- this is clear now! Best, É.
Le 25 juin 2019 à 21:26, Tomas Rokicki <rokicki@gmail.com> a écrit :
If you require all differences to be unique, then you're looking for a Golomb ruler. If you require all differences to be unique *and* you want to measure all values 1..200, then you're looking for a perfect Golomb ruler. There are no perfect Golomb rulers with more than five marks (measuring distances 1..11).
On Tue, Jun 25, 2019 at 11:22 AM Éric Angelini <eric.angelini@skynet.be> wrote:
Hello Math-Fun (posted here as SeqFans didn't publish my mail) 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. Best, É.
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