Question

formule for this table?

Answer 1

? are you asking what must be done to the numbers to total to 15?

Answer 2

I believe it's called the magic square, using the formula:
M=(n*(n^2+1))/2
M: is the sum (15 in ur case)
n: length of square (3 in ur case)
here's the link to explain: http://en.wikipedia.org/wiki/Magic_square

Answer 3

also can be generated with matlab software, using the command:

>magic(3) ;