This is also written as
an3b3 . . .bn
where the numbers
(n r) ! r !
are called binomial coefficients. Table 1 gives some binomial coefficients.
where a n
r0 signifies that the terms which follow are to be added (summed)
starting with r/0 and ending with r/n . Thus, for example,
where use has been made of the entries corresponding to n/4 in the above table.