4 The second floor, or1*10+3 * 9+5 * 8+7+9 * 6+1* 5+13 * 4+15 * 3+66.
Nine are on the third floor,
The fourth layer has 16, (3): the nth layer has n squares.
25 on the fifth floor,
No.36, sixth floor,
49 on the seventh floor,
64 is on the eighth floor,
9/f 8 1,
10th floor 100.