i have 4 different numbers in two columns say A & B. i want to
multiply them & get the result in column C, multiplication should be
done in the following manner:-

C1= A1*B1
C2= A2*B1+B2*A1
C3= A1*B3+A2*B2+A3*B1
C4= A1*B4+A2*B3+A3*B2+A4*B1

can you please help me in this?