Listener 4101 - Primordial by Viking

[daagg]

Oh dear, that was far too easy! A quick trawl through my Dictionary of Interesting Numbers and a short jigsaw puzzle.

[silversolver]

Been away on holiday for a couple of weeks - managed to buy overseas editions of the Times and completed Pointer's Double Devilry without too much difficulty but last week's superb epic from Kea whiled away many hours and had to wait until my return to be completed. I agree that this week's offering was very easy by comparison although enjoyed putting it together.

[trux]

Had guests staying all weekend, who only left yesterday afternoon - so only got down to it then - and regret that I must agree with all other "threaders" here. Yes, pleased to finish a numerical, but really not very satisfying .... so, ALL OF YOU, get your brains into gear and start designing a better puzzle for next time !

[Clamzy]

If you want a better one I can repeat my offer from earlier this year of Higher Powers by Leon.

[twoshortplan]

Started this today and it looks like an easy one as numerics go. Odd that some entries are not clued (12A, 21D etc.) Viking might have said that any unclued entries are just plain old primes.

[Zabadak]

Hi Twoshortplan. First line says: "The grid entries are distinct prime numbers, with all their digits odd." It's how I knew on my first shot that I was going wrong, as I had one of those unclued numbers with an unchecked square, and there were alternatives.

[Mysterons]

....... but the alternatives would eventually be ruled out as they would appear elsewhere in the grid, so you wouldn't necessarily know at an early stage.

[Philoctetes]

I have a continuing problem with whether to include zeros in these puzzles. They cannot be divided exactly by 2, so they are not even; even the act of dividing is impossible, so they cannot be divided and leave a remainder, so they are not odd. Is there a Listener ruling on this?

[Zabadak]

Not the way I had it, Mysterons - I was going down a blind alley at the time because I had failed to produce an accurate set of relevant numbers. Hard to explain now, but it sent me back to basics and a more rewarding effort.
For Philoctetes, all I think I could suggest from here is trying the problem with, or without the numbers containing a zero. One set works. The other doesn't.

[Mysterons]

Thanks for the clarification Zabadak - I had assumed you were referring to the 3 possibilities for 44 across.

Philoctetes - it's often assumed that zero cannot be divided exactly by 2, but in fact it is an even number:

http://en.wikipedia.org/wiki/Parity_of_zero

[Philoctetes]

Thanks for the link - I had completed some time ago, having realised that one set was impossible fairly promptly. But, as a non-mathematician, zeroes always get my goat.