You don't define arrays as IBOutlet. IBOutlets are things that you can put on the interface(buttons, label, views).
Probably a good way is to change the tags of the button to numbers in interface builder. Then all you got to do to access the tag is something like...
Someone back me up if this is right cause I think it will work...
I think the [sender titleForState:UIControlStateNormal] might also help define your buttons