Keith,

As it happens, while changing channels today I heard a preacher talk about the significance of the number 153 in the Bible chapter John 21 (I changed channels before he explained it). But then, later in the same day, I see this number on your website: You mentioned that your maximum heart rate in a bicycle rally was 153. It must be Fate!

A Google search on “153 John 21” produces, among other sites, this. So it looks like there is a whole world of Bible numerology that I never knew about. Here’s an alleged fact that begs for a proof:

Take any positive-integer multiple of 3, such as 21. Take the sum of the cubes of its digits. For 21 you get 2^3 + 1^3 = 8+1 = 9. Then subject your new number to the same procedure. There is only one digit in 9, and its cube is 9^3 = 729. Now find the sum the cubes of the digits of 729: 7^3 + 2^3 + 9^3 = 343 + 8 + 729 = 1080. Keep going in this way. The claim is that you eventually will reach the number 153. Let’s call this transformation “f.” So far we have f(21) = 9, f(9) = 729, f(729) = 1080, f(1080) = 1^3 + 0^3 + 8^3 + 0^3 = 1 + 0 + 512 + 0 = 513, f(513) = 5^3 + 1^3 + 3^3 = 125 + 1 + 9 = 153. Yes, we arrived at 153. Moreover, we stay there forever after, because f(153) = 1^3 + 5^3 + 3^3 = 1 + 125 + 27 = 153.

Mark Spahn (West Seneca, NY)