I don't think that's very funny.
Edit:
Ummm, did you ever learn algebra?
That formula you gave proves nothing other than 1 x 2 = 2.
The formula that is used in geometric patterns is:
S = a + 0.5b
so, if a is 1 and b is 1, then S = 1 + 0.5(1) --> S = 1.5
to continue the progression, we assign...