Jasper Yu says to YSITD a=0 d=[] for (i=0; i<10-1; i++){ d.push(0) } d.push(1) for (r = 0; r < 20; r++){ console.log(a, d) for (i=0; i<d.length; i++){ if (i-1 >= 0){ d[i-1]+=d[i] } } a+=d[0] }