Consider the series of semiprimes. Now consider the series of numbers representing the Sum Of Digits (SOD) of each semiprime.

(1.) How many times does the number '9' occur, and why?

(2.) What is the smallest semiprime that has the same SOD as the next consecutive semiprime? or prove that there is no pair of consecutive semiprimes that have the same SOD.

(In reply to Puzzle Answer by K Sengupta)

146 is the smallest semiprime that has the same sod(=11) as the next consecutive semiprime, which is 155.

Posted by K Sengupta on 2024-01-07 12:10:45