User talk:Baijiangchen
Revision as of 00:20, 22 July 2012 by Baijiangchen (talk | contribs) (Created page with "If: <math>W(0):=1</math> <math>W(n):=\sum_{i=0}^{n-1}({n-1 \choose i}W(i)(x-i-1)!(2^{x-i-1})</math> Then: W(n)=(2n-1)!!")
If:
Then: W(n)=(2n-1)!!
