# You're reading: Posts By Paul Taylor

### GCHQ Christmas puzzles winners and solutions announced

The first puzzle is a super-fun 25×25 nonogram puzzle

Before Christmas, the benign megasurveillance bods at GCHQ released a set of festive puzzles, in the form of a Christmas card and associated website. An initial nonogram puzzle led to a sequence of increasingly fiendish teasers, and solvers of the final set of puzzles were invited to email in their answers, with the correctest winning a fancy paperweight, signed book and, GCHQ were at pains to stress, not an Imitation-Game-style secret job offer.

### Timothy Gowers has launched a new arXiv overlay journal

Sir Timothy Gowers has announced on his blog a new journal, Discrete Analysis, of which he will be the managing editor. Rather than a traditional journal, this will be an open-access ‘arXiv overlay’.

### UK National Lottery: now 21% more balls (rounded up)

This week, it was announced that from October the UK’s National Lottery, currently operated by Camelot and already providing a veritable Merlin’s cave of probability lessons for maths teachers, will be changing the rules for its main ‘Lotto’ draw. The main changes are that a new £1m prize will be added to the raffle element you didn’t know already happens, and that matching two balls will win a free ‘lucky dip’ ticket in the subsequent draw. The fixed £25 prize for matching three balls remains on the round table (even though it sometimes causes hilarious number gaffes).

But the Sword of Damocles hanging over Camelot’s changes is that there will be an extra ten balls to choose six from (59 instead of 49), dramatically lengthening the odds of winning all of the pre-existing prizes. This is our round-up of the media’s coverage of this mathematical “news”.

### π and the Mysterious Excel Function

Users of Microsoft’s flagship 2D-array-based data-organisation tool Excel will be aware of some if its more recondite functions. From the occasionally useful

RIGHT: returns the substring of a given length from the right-hand end of a cell’s contents

to the wilfully obscure

### Further information

The Great Internet Mersenne Prime Search (announcement on the front page as of November 10)

Their page for the prime itself

Mersenne Prime at Wolfram Mathworld

via @mathupdate on Twitter