[seqfan] Re: intersection patterns of n sets

[Joerg Arndt]

I narrowed it down a bit:
number of {0,1} matrices with n columns and 1...2^n-1 rows
without all-zero columns, distinct columns, and modulo
some equivalence (permutations of both rows and columns???).

starts (n>=0) as 1, 1, 4, 20(?)

I looked at quite a few sequences starting 1, 4, x for
x=18, ..., 22 and so far could not find anything pertinent.

Best regards,   jj