Listener Crossword No 4308 Sub-Prime More-Guess Relief By Ruslan

[BobHWW]

A fairly easy solve in contrast to the rather complicated preamble. I haven't tried to work out the title yet!

Farewell Ruslan - you will be missed.

[Scorpius]

Hmmm. Everything seemed to be progressing smoothly with twelve entries and about half the grid filled, until I looked at the first 3 digits I have for 12ac, which, as far as I can see, could not begin a viable answer to 12ac satisfying the clue conditions, since it's not prime, and adding any fourth digit fails to make it prime.

Nothing for it but to begin again - one of the reasons I'm not particularly keen on the numericals.

[emcee]

I enjoyed it although it wasn't difficult -- despite the preamble. There was one key point for me where it was easy to forget one of the possibilities for one of the 4 digit grid entries.

I will miss Ruslan's puzzles. RIP.

[Oyler]

I assumed that we'd seen the last of Ruslan's quirky puzzles. How pleased I was to have my assumption proved wrong. A very fine swan song.

[JustinTime]

What an excellent numerical. Less than two hours of my time spent (wasted) solving it.
Keep them this simple and we numerical haters will have less to complain about.

[starwalker]

Pleasant, if at times frustrating solve.

Scorpius, I think you made have made the same mistake which I did early on and overlooked a possibility for 12 down.

[Scorpius]

Starwalker, I did overlook a possibility for 12dn, but that hasn't resolved things. Having made one error, I started again and proceeded in a very thorough and methodical way, discovering one clue that has only one possible answer, and others that had only two. However, having filled the whole grid apart from 12ac and 12dn, and having found two possible prime candidates in column 6 (3 digits and 4 digits) I cannot get the maths to work to give an answer that's fits the conditions for 12ac and fits what I have in the grid.

Am I the only one having problems with 12ac? All very frustrating, because the maths is basically very simple.

[Scorpius]

Sorry. Ignore the previous message. I misread a figure in one of the possible prime factors for 12ac. All finished.

Is it possible to delete a message that one has posted? If so, how?

[Ruthrobin]

Scorpius, if you 'report' the message (right click at the bottom) and say that it is your own that was an error and shouldn't have been published (or, as has been occasionally done - give a very good reason for someone else's message being deleted - if, for example, it was offensive or spelled out the solution to the crossword) it will disappear some time later - can be minutes or hours.

[Cagey]

Another good numerical. Had very busy weekend and could only tackle last night after ironing 5 of the teeniest shirts imaginable for eldest starting school (alas they have not phased such things out since I was forced to attend... surely science can come up with (many) things better). So late start, but happily early finish. As others have stated a steady solve, and an interesting way of coding.
As a solver of just over a year or so, I am not very familiar with Ruslan can anyone suggest others by him to tackle?

[s_pugh]

Well this is one numerical virgin who isn't hooked. After reading and re-reading the preamble I still can't fathom it, but then as a self-confessed maths dunce I never learned about 'prime factors' and even the BRB doesn't seem to have heard of them either. Perhaps if the already long-winded preamble had included an example of how the clue format led to an answer it might have engaged a bit more and given some of the more mathematically-challenged a bit more to go on.

[Ruthrobin]

The internet provides a prime number list that has all that you need: http://www.mathsisfun.com/numbers/prime-numbers-to-10k.html
If you email me at [email protected], I (also one who has difficulties with the numerical ones) can help you with the preamble, as this one was nowhere near so difficult as usual.

[jim360]

If you want help get in touch s_pugh... my email is available via the crossword.org.uk forums if you look for the "James" there.

[tristram37]

I agree with Ruthrobin that this was not as difficult as usual. I am usually defeated by the numericals but by constructing a fairly simple spreadsheet I was able to make steady progress to the solution having made, much to my surprise, no errors on the way. But I also agree with S_pugh that an example of how the grid entries were arrived at would have been helpful.

[aldanna]

I do not find numericals interesting but Himself did it very happily, and reckoned it was fairly straightforward.

[crosswhit99]

Using 1 down as an example, the sum of the two primes must be 124, 126 or 128, being (21 x 6) plus or minus 0 or 2. As their product has 4 digits but the grid entry only has 3 digits, they must both be 2-digit primes, differing by less than 9. Only 2 of the 15 combinations yield a pair of prime numbers - the correct choice is determined by checking cells.

[Scorpius]

Im puzzled by the last sentence of the preamble. The discovery of the other factor for 12ac in column 6 is not necessary, and 12ac can be worked out without any guesswork. If one has a comprehensive list of primes, the unchecked cell can be filled in and the other factor worked out mathematically from the clue. There's no guessing anywhere.

[UglyUncle]

Coming in late as usual, I wasn't going to post a message, but then I read Scorpius's final contribution and thought, 'I must at least endorse that comment'. I solved 12ac and 12dn last, so I already had the last three digits of the former in place; the potential variation in the first cell and the gap in the fourth could be resolved by choosing the only available prime factor, whereupon the other prime was perfectly clear. I have a full grid and can't see any other possible solutions that could have resulted in ambiguity.

A nice touch (it's happened before - perhaps in a previous Ruslan) was the momentary panic, quite early in solving, of finding an apparently unresolvable ambiguity at the intersection of 3dn and 10ac. Then I re-read the preamble!

[olichant]

A bonus spin-out puzzle from this, incidentally, is to show why the first sentence of the preamble is correct...

[roslyn251254]

I'm a numbers person, so once the preamble was properly understood(took a while!) and a few answers filled in the rest came easily with very few alternatives.
Nice puzzle for a wet bank holiday Monday!

[British_Olympics]

... every prime number is odd (so every adjacent number (+1 or -1) has to be divisible by 2) and (apart from 3) not divisible by 3 (so one adjacent number must be), therefore one adjacent number is divisible by (2 x 3) = 6.