automated Text or SMS app or program

I need a program or an app that can send automated or pre text to a #, you do NOT need to make the program or the app, I just need a program or an app that is capable of doing this. it can be premade or an existing program. The program must take the # I give it to and send text messages to it. This should be from different phone #, The phone # will be in North America. the sender phone # can be from anywhere. but sender phone # needs to be changed after around 40 to 80 messages sent.