1 / 3 + 1 / 15 + 1 / 35 + 1 / 63 + 1 / 99 + 1 / 143 + 1 / 195 It should be easy to understand

1 / 3 + 1 / 15 + 1 / 35 + 1 / 63 + 1 / 99 + 1 / 143 + 1 / 195 It should be easy to understand


One in fifteen = (1 / 3-1 / 5) * 1 / 2, one in thirty-five = (1 / 5-1 / 7) * 1 / 2, and so on