>>191
Sum[n4=40-n1-n2-n3;Boole[n1>1] Boole[n2>1] Boole[n3>1] Boole[n4>1] Multinomial[n1,n2,n3,n4] (4/10)^n1 (3/10)^n2 (2/10)^n3 (1/10)^n4,{n1,0,40},{n2,0,40-n1},{n3,0,40-n1-n2}]
= 17931735688870232246983662877718870163/19531250000000000000000000000000000000
= 0.918104867270156...

Booleの積を　Boole[Boole[n1>0]+Boole[n2>0]+Boole[n3>0]+Boole[n4>0]==3]　に置き換えると>>156に使えるが、牛刀