Delphi常用数值算法集：Delphi常用数值算法集.ZIP

				Function ASS(N:integer; B:real):real;
				var
				    DB:real;A:array[1..15] of real; I:integer;
				begin
				    A[1]:=Exp(-B) / B;
				    If N = 1 Then
				      ASS:=A[N]
				    else
				    begin
				        DB:=1 / B;
				        For I:=2 To N do
				          A[I]:=A[1] + DB * (I - 1) * A[I - 1];
				        ASS:=A[N]
				    end;
				end;