How do i calculate the row in straight table

[#1]

Dear All,

         how do i calculate row wise values in report

eg :

row 1

row2

row3

row4

   row 1 = 0

in row 2 = row1 + row2 + row3

in row3 = row2 + row3 + row4

i need above output

Can any one help me!

Regards,

Napolean.