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50 10 50 n 10 m n∨=m 10 50 49 48 41 50 49 48 41=37276043022296000 n m n∨=m pmn=n n-1 n-2 n-m+1
50 10 10 10 C1050 C1050 1098 21=P1050
C1050= p1050/10 9 8 2 1= p1050/p1010
n m m=∧n n m Cmn Cmn=Pmn/Pmm