Re: GCHQ Monday Puzzle

On 06/05/2025 07:02, David Entwistle wrote:

On Mon, 10 Feb 2025 08:59:23 -0000 (UTC), David Entwistle wrote:
 

I'm sure many of you know that GCHQ publish a puzzle each Monday on
their X account. For any that don't:
>
https://x.com/GCHQ

 There's been no GCHQ Puzzle this week - Monday was a bank holiday in the
UK. This one is from the excellent GCHQ Puzzle Book 1.
 125. Number Sequence IV
(a) 7, 8, 5, 5, 3, 4, 4, ?
(b) 2, 2, 2, 3, 2, 2, 4, 2, 3, ?
(c) 1, 2, 3, 2, 1, 2, 3, 4, 2, 1, 2, 3, 4, 3, 2, ?
 I think I know (a) and (c), but not (b), as yet.

You do know (a). Even /I/ know (a).
You may well know (c), although I can't see it myself.
(b), however, is just one of their 'read my mind' puzzles that they love to waste people's time with. A good cryptographer tries not to leave any hooks you can pick at. A good puzzle setter tries to be fair to the solver by leaving at least /one/ hook. GCHQ is packed full of good cryptographers.
--
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
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