Numbers

1 + 2 + _ _ _ + 63 = 2016. So the problem is equivalent to finding the number

of subsets of{1,2,…..,  63} whose sum of elements is 8. We can count this manually : {8}, {1,7} , {2,6} , {3,5} , {1,2,5} , { 1,3,4}

Hence , 6