how do i store a value when using animation nodes? I am translating a list of objects but I only want the translation in the x,y,z plane to occur during frame one then after frame one the translation to happen only in the x,y plane. 

Any help is appreciated.
I found a way to create the numbers that I needed. I created a line of vertices that were in the z range that I wanted, then made sure the vert count was equal to my particle count. I then iterated the vert locations through the loop and separated the z values and reinserted them into the translation data. Thank you for all the help and suggestions. They looked viable just a lot more complicated.