Why stop at three? Call him every day, every hour on the hour, until he capitulates and agrees to go out with you just to make you stop calling, or gets a restraining order against you.
Actually, never mind, that's probably not a good idea.
Call him once. Anything more will make you look desperate and possibly psychotic. One call is enough to let him know you are interested. If he calls back, great. If not, move on. After you boil his bunny, that is.