13！/(2!2!2!2!）-4*12!/(2!2!2!）+6*11!/(2!2!)-4*10!/2!+9!

来源: AceOnRiver 于 2009-11-05 13:53:05 [] [旧帖] [给我悄悄话] 阅读数 : (56 bytes)

same reasoning as 恶狼, slightly different coefficients.

请您先登陆，再发跟帖！