Question 753607
For each pair of rows on the bottom layer, there are 7 positions where 4 balls meet, and there are 7 such pairs of rows on the bottom layer.
Similarly, for the 3rd row there are 6 positions for each pair of rows and 6 pairs of rows.
And so on, up the pyramid.
So the number of balls in successive rows are squares of integers counting down from 8:
8^2,7^2,6^2,...
64+49+36+25+16+9 = 199
So there is one ball left over