Let there be n buttons. A player may take 1 or 2 buttons MORE than his/her opponent took. Player 1 can take either 1 or 2 buttons.

e.g. 28->27->25->21->15->7->0

(the last player must take either 8 or 9, as only 7 remain, they must take them all).

What are the strategies for various n, with either last button wins/loses?