The answer to yesterday's question is A9, as dougs rapidly worked out. The numbers are squares in hexadecimal notation; the first three are therefore 1, 4, and 9, followed by 10 (= 16), 19 (= 25), 24 (= 36), 31 (= 49), 40 (= 64), 51 (= 81), 64 (= 100), 79 (= 121), and 90 (= 144). The next is 169 in base 10 which translates to A9 in base 16, A being the usual notation for the number next after 9. crumpetsfortea was nearly there, but dougs nailed it.

drplokta asks in response what comes next in this series:

14, 23, 28, 34, 42, 50, 59, 66, 72, 79, 86, 96, 103...

The answer is 110, or Cathedral. Obvious when you know why.

Idly googling my ancestors in the hope of getting some genealogical insight is one of my occasional harmless pastimes. I have struck gold for once with this story from the archives of the Correspondence Chess League of America (at least, from context, I guess that is what CCLA stands for): ( Read more... )