[seqfan] Anyone looking for a nice problem?

Neil Sloane njasloane at gmail.com
Wed Mar 9 05:50:14 CET 2022

I've been going through my 50-year old scans of pages from  L'Intermédiaire
des Mathématiciens, and in volume 26 (from 1919) I found a triangle from
the great Belgian mathematician Paul Poulet that did not make it into the
OEIS until exactly 100 years later,  A326411.

Poulet's definition seems easier to understand than the recent one, so I
scanned his article, see the entry. The photocopy I have is not great, so I
scanned it at 600 dpi.

The problem is to find a general formula for the entries.  As far as I can
tell, neither Poulet nor Tatkiewicz found a formula that explains the whole

There are connections with A002816 and A002464.

Best regards

Neil J. A. Sloane, Chairman, OEIS Foundation.
Also Visiting Scientist, Math. Dept., Rutgers University,
Email: njasloane at gmail.com

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