counting, combinations, b integers with constant sum s

[Ron Baker, Pluralitas!]

If you have b non negative integers that sum to
s the number of possible combinations is
nchoosek( s+b-1, s )

Anybody know the rationale/proof behind that?
Or a link to a page explaining it?

TIA,
rb

[Ron Baker, Pluralitas!]

Post by Ron Baker, Pluralitas!
If you have b non negative integers that sum to
s the number of possible combinations is
nchoosek( s+b-1, s )
Anybody know the rationale/proof behind that?
Or a link to a page explaining it?
TIA,
rb

Never mind. I found it.

--
rb