Prize crossnumber, Issue 22

Our original prize crossnumber is featured on pages 58 and 59 of Issue 21.

There is only one solution to the completed crossnumber. Solvers may wish to use the OEIS, Python, relevant episodes of Numberblocks, etc to (for example) obtain a list of prime numbers, but no programming should be necessary to solve the puzzle. As usual, no entries begin with 0.
One randomly selected correct answer will win a £100 Maths Gear goody bag, including non-transitive dice, a Festival of the Spoken Nerd DVD, and much, much more. Three randomly selected runners up will win a Chalkdust T-shirt. Maths Gear is a website that sells nerdy things worldwide, with free UK shipping.
To enter, submit the sum of all the digits in the row marked by arrows using this form by 14 March 2026. Only one entry per person will be accepted. Winners will be notified by email and announced in issue 23.

Crossnumber #22, set by Humbug:

Chalkdust dissertation prize winner 2025
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What’s hot and what’s not, Issue 22
Fashion is fleeting, Chalkdust regulars are not.
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