[seqfan] interesting idea, weird ramifications, as yet unsolved

[Wouter Meeussen]

“Pairwise combinations of distinct elements”
see https://math.stackexchange.com/questions/3708151

my feeling is that Algebraic Combinatorics should clarify this, reducing it to a well known pattern.
I tried but failed dismally.

It boils down to a list of monomials X_(k+1) generated by

(X_k ** X_k  - X_k . X_k )/2 where “**” represents the outer product.

The author (‘Cesare’) only asks for a very limited property of these multinomials, but there is a lot of other ‘enumerative combinatorics’ going on here.

Does anyone recognise the patten?

Wouter.