24 Apr
2007
24 Apr
'07
9:53 a.m.
On Mon, 23 Apr 2007 at 04:36PM -0700, Stefan O'Rear wrote:
I'm finding the number of set partitions that correspond to a certain integer partition. If p = p_1, p_2,...,p_k is an integer partition of n, then there are
n! ---------------------------------------------- p_1! * p_2! * ... * p_k! * 1^c_1 * ... * k^c_k
That formula isn't even correct. Consider p = replicate n 1, that is n partitions each of size 1. There is only one way to do this - put each element in its own partition. However, your formula gives:
Correct, the formula is incorrect. :) The "i^c_i" terms need to be c_i!. (I got it right in my code, though.) Dan -- Ceci n'est pas une .signature.