Write out the first 15 primes all on one line. On the next line, underneath each pair, write the difference between the larger number and the smaller number in the pair. Under this line, below each pair on the previous line, write the difference between the larger number and the smaller number. Continue in this manner. Your “triangular” table should begin with: Once your chart is made, imagine that all the primes were listed on that first line. What would you guess is the pattern for the sequence of numbers appearing in the first entry of each line? The actual answer is not known. It remains an open question! What do you think?