That is, 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 = 120; and 1 + 3 = 4 + 5 = 9 + 7 = 16 + 9 = 25 + 11 = 36 + 13 = 49 + 15 = 64, giving us the numbers 4, 9, 16, 25, 36, 49, 64, the squares of 2, 3, 4, 5, 6, 7, 8.