Incremental cell block (A1+2 = A3.....is it possible ???)

For example, I have a data like this :

	A	B	C
1	Brad	Judith	A1+2=A3
2	Emile	Carmen	A3+2=A5
3	Judith	Agustine	A5+2=A7
4	Philip	Chris	A7+2=A9
5	Carmen
6	Mark
7	Agustine
8	Mike
9	Chris
10	Merry

The result supposed to be like in column B (I wrote the formula like in column C, but it give me #VALUE)
Because the data is so many, It take hours to do manually.... is there a way ?

Any suggestion ?

Many thanks !