Tables of combinatorics

I would like to automatically create a table of combinatorics in Excel. For instance there are 6 ways of choosing 2 things out of 4.

The table is simple enough to construct by hand:

combin(4,2)=6

	1	2	3	4	5	6
1	1	1	1	0	0	0
2	1	0	0	1	1	0
3	0	1	0	1	0	1
4	0	0	1	0	1	1

I see some third party add ins to Excel that do this. Any suggestions? Has anyone tried this kind of software before?

You're just counting in binary (look vertically). Use Dec2Bin(x) and then break it out into individual bits.

Edit: to be more specific, count from 0 to 2^N-1, separate the N bits into columns, and then count how many of them are 1. Filter by count = M, and that's your table of C(N,M).

It seems logical, but it is a little computationally intensive.
Combin(25,8)=1,081,575 . The filtering means you have to generate a lot of useless numbers. It might work however, but not in a spreadsheet.

Try this:
http://graphics.stanford.edu/~seander/bithacks.html#NextBitPermutation

The very last method on that page should be doable in a spreadsheet (or in a VBA macro), and it won't produce any unused data.