[seqfan] Non-square composite numbers

[Maurice.Clerc at WriteMe.com]

By studying how to pave the space with parallelepipeds I was led to
define the following sequence:

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List of integers so that each one after (2,3) is the product of k=2
different previous ones in the list. Duplicates are not allowed.
Example:
2 3 6 12 18 24 36 48 54 72 108 144 162 216 288 324 432 648 864 972 1296 1728

Note 1: they are not classical "composite numbers".
Note 2: it could be generalized for k>2.

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and also ;
- the similar one with duplicates.
- the similar ones without any square.

They don't seem to be in OEIS, but do you think it is worth adding one
of them (or more)?
I am not sure they are of "general interest", as required.

Regards
Maurice