in reply to Re^6: combinations of given string
in thread combinations of given string

It looks like the number of w-combinations from a set of c+w elements: C(c+w,w) = (c+w)!/(c+w-w)!w!

Yes, that's probably it.

I mean, that is definitely the derivation of the formula; and it is probably where I recognise it from. Still, there is an itch in the back of my brain that is associating it with something quite different?

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