Our original prize crossnumber is featured on pages 58 and 59 of Issue 17.

- Download Crossnumber #17 as a PDF, or read on!
- Submit your answer

### Rules

- Solvers may wish to use the OEIS, Wikipedia, Python, a slide rule, etc to (for example) obtain a list of cube numbers, but no programming should be necessary to solve the puzzle. As usual, no numbers 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**23 September 2023**. Only one entry per person will be accepted. Winners will be notified by email and announced on our blog by 1 November 2023.

### Crossnumber

Crossnumber #17, set by Humbug:

### Across clues

- 1. An anagram of 3D that is a palindrome. (5)
- 4. An anagram of 7A. (4)
- 6. A multiple of 51A. (3)
- 7. 7 times 4A. (4)
- 9. The number of the down clue whose answer is equal to the number of white squares in this crossnumber grid. (2)
- 10. Every digit of this number is even. (3)
- 12. 5 more than a palindrome. (7)
- 16. 7 times 6A. (3)
- 17. The number of the across clue whose answer is 17. (2)
- 18. The first four digits of 19D. (4)
- 20. One more than the product of 38A and 38D. (5)
- 21. The number of the across clue whose answer is 21. (2)
- 22. Every digit of this number is the same. (6)
- 27. The sum of this number’s digits is 5. (6)
- 30. An anagram of 86420. (5)
- 31. An anagram of 19D. (7)
- 32. The number of the down clue whose answer is 131. (2)
- 33. The sum of this number’s digits is 5. (6)
- 35. The sum of the digits of 35D. (2)
- 36. A multiple of 46A. (4)
- 38. An even number. (3)
- 40. A multiple of 51A. (5)
- 43. A multiple of 11111. (5)
- 45. 5 more than a palindrome. (3)
- 46. A multiple of 3. (3)
- 47. An anagram of 9630. (4)
- 48. An odd number. (2)
- 49. The number of the down clue whose answer is 653. (2)
- 51. Greater than 9A. (2)
- 52. 5 more than a palindrome. (4)

### Down clues

- 2. A palindrome. (4)
- 3. An anagram of 1A that is 5 more than a palindrome. (5)
- 4. The sum of the digits of 24D. (2)
- 5. A square number. (3)
- 6. The last 6 digits of 12A. (6)
- 8. The number of distinct pentominoes* that can be made. (2)
- 9. An odd number. (3)
- 11. 5 more than a palindrome. (11)
- 13. A multiple of 3. (5)
- 14. The number of the down clue whose answer is 11. (2)
- 15. The number of the down clue whose answer is 15. (2)
- 19. Each digit of this number (except the first) is less than or equal to the previous digit. (7)
- 22. The product of 39D and 17A. (5)
- 23. One more than 34D. (2)
- 24. An odd number. (4)
- 25. The final digit of this number is the first digit of 5D. (3)
- 26. 15D squared. (3)
- 27. 20 less than 29D. (3)
- 28. 10 more than 27D. (3)
- 29. 10 more than 28D. (3)
- 34. One less than 23D. (2)
- 35. An odd number. (3)
- 37. A multiple of 9. (5)
- 38. An odd number. (2)
- 39. An odd number. (3)
- 40. The sum of this number and 50D is 26D. (3)
- 41. The number of the down clue that is equal to 48A squared. (2)
- 42. The sum of this number’s digits is 11. (4)
- 44. A multiple of 1111. (4)
- 46. The number of the across clue whose answer is 1089. (2)
- 50. 5 times 8D. (2)

* A pentomino is a polygon made by joining five squares edge-to-edge. Pentominoes that are rotations of each other are considered the same, but those that are reflections of each other are considered distinct.