significance of this recursive function

Want to know the significance of the following function

var abc=(function(a, b){
    return a == 0 ? 0 : abc(a -1, b) + b;
});
(function(){
    var a = abc(10, 10);
    console.log(a);
})();

I know the output of the following function is 100 but what is it call in Mathematics?