Let's re-write the table in terms of i:

iMultiplyAdd~Pi
11 (= -12) 4/(2*1-1)4
2-1 (= -13) 4/(2*2-1)~2.666
31 (= -14) 4/(2*3-1)~3.466
4-1 (= -15) 4/(2*4-1)~2.895
51 (= -16) 4/(2*5-1)~3.339
6-1 (= -17) 4/(2*6-1)~2.976

Now that's starting to look a bit more like something that could be turned into a for loop ... all that's left is turning the exponents (like -13) and denominators (like (2*3 - 1)) into expressions with is.