Countif without duplicate in filtered cells

Hi all experts,

I have a formula as follow:
=SUMPRODUCT((AX2:CU198>AY1-1)/COUNTIF(AX2:CU198,AX2:CU198&""))

I want to make it only shows the result in filtered cells. Please help! Thanks very much!!!

http://www.mrexcel.com/forum/excel-q...-function.html

Dear Tim,

Thanks for the reference. Hope I can understand and make it after study. ^^

After several hours of study, I still can't make a right formula. The following is one I have tried, however it is surely wrong

=SUMPRODUCT((AX2:CU198>AY1-1)/SUMPRODUCT(SUBTOTAL(3,OFFSET(AX2,ROW(AX2:CU198)-MIN(ROW(AX2:CU198)),0,1))*(AX2:CU198=AX2:CU198)*(AX2:CU198="")))

Any masters can give me some help. Thanks!

Can someone help? I really cannot solve the problem until now. Thanks!