18 задание free pascal
Var N:integer; P:real; Begin Write('N = '); ReadLn(N); P:=1; For N:= 1 to N do P:=P*(N*2-1)/(2*N); WriteLn('P = ',P:0:5) End. N = 50 P = 0.07959 N = 100 P = 0.05635 N = 200 P = 0.03987