Listener No 4270 Alma Mater By Oyler

[Ruthrobin]

Full marks, Oyler! Sheer joy to have a numerical Listener with a theme. I never thought I would open the thread for a numerical. This will make our Listener year!
Yippee - great fun!

[EAChaplin]

My thanks also to Oyler for a fun puzzle which I did savour. Thanks also to Drb for the guide to wolfram as I had failed to find such a source. The windows scientific calculator gave a string of digits falling well short of the 133 required and terminating in e+132, which I understand means multiply by 10^132 - no thanks.

[Oyler]

I have written a blog which will appear in three weeks time at listenwithothers which will detail the setting process along with lots of background material or waffle!!

[dr b]

Oyler, point taken re savoring, but if you see an obvious path to a quick finish, does it makes sense to ignore that path and make it harder than it needs to be?

[Oyler]

OK fair enough dr b but what if the obvious path or guess turns out to be wrong? You'd have wasted time on it!! Better to follow the logic.

[Staurologist]

Certainly one to help relieve the blues, and much saltier than many other number puzzles. I agree with Oyler. Much more fun to follow the logic and work it all out using a simple calculator than to write a computer program to do the work for you, especially if, like me, it would probably take you longer to write the program than to solve the puzzle :>). In this case, for instance, using the modular approach to solving the last two digits of the powers, which avoids the need to do all the multiplications, gives you an extra insight. For number puzzles I find the tables in, for example, "The Penguin Dictionary of Curious and Interesting Numbers" by David Wells or "The Number File" by Adrian Jenkins very useful.

[jim360]

On a puzzle like this it was possible to do about half the calculations by hand. Indeed the preamble information alone cuts the number of options from about 640,000 million million to about 160,000 (four different options of eight primes) and then from there you only handful of clues to constrain that parameter space very tightly indeed. About half the time I spent on this puzzle was completing the calculations having got the eight values and then worrying about what the theme was. Anyone writing a computer program to solve this one either enjoys writing computer programs or enjoys wasting their time.

[Contrarian]

Jim360,

How did you solve Radix's Boxes puzzle?

That was a clearer example of a problem which invited a (pretty challenging) solution using logic, or which could be solved trivially with a few lines of code.

[jim360]

With a calculator and a lot of patience. I certainly didn't spot the logical route, and as a result it took my most of a weekend.

[teuchter2]

Excellent fun, though I took longer than I should have done to find the further occurrence of the dates in the grid. I should have had more awareness of the likely theme. I managed to get it all done apart from this last step by 6pm, using a basic calculator and devising a way of looking at patterns to get the last 2 digit answers.

[trux]

For those of you now with plenty of time on their hands, might I suggest you try the Sabre in the Magpie? I can confidently predict that it will take anyone more than 5 minutes. (Am all done now but it was a tough ride along the way).

[Scorpius]

A straightforward solve apart from those enormous powers, with only a limited number of permutations for the 8 letters. I found four sets; not sure if there are any more, but one of my four worked. Thanks Drb for the Wolfram Alpha reference. I'm pretty sure I've not made a mistake, but I cannot see any date elsewhere in the grid that will match the digits I have in place for 31. For 1ac I can see three possible dates.
Will have to check my working again.

[magwitch]

Jim - I think the preamble immediately cuts the number of options to 1287 (any 8 from 13), and it is a fairly simple matter to show that only 5 of these satisfy the 600 condition.

[Cruncher]

Found it tough to crunch out the first value but thereafter it was a gentle stroll. Certainly less perspiration required than the infamous Boxes

[Scorpius]

I got there (with some help from Google), but more by a hunch than by finding the duplicated dates in the grid. Even when I was convinced of my solution by an unexpected PDM, I didn't immediately spot the duplications until I got out a ruler to experiment with straight lines.

I agree with others that it was a very nice numerical with a bit of non-numerical stuff to add interest. I'm not a great fan of number puzzles these days, but I've always found Oyler's very fair.

[Cagey]

Just back from hols to do last few weeks puzzles. Both great.
I agree with Magwitch that there are 5 sets but Jim360 that there are lots of orders of these. I was also rather lucky with a bit of general knowledge on this one, which meant could fill in 17 squares from deduction alone and no maths.

[sunny-dave]

Yay - good fun that - numericals were the first Listeners I ever did, but these days I tend to sigh a bit when they arrive .

Not this one though - lots of thematic content, a reasonably tough logic problem to find a way into the gridfill and a nice picture at the end.

Thanks Oyler.

[Philoctetes]

A very straightforward logical thread through this one, with no recourse to the calculator till quite late on. I am surprised people got so hung up on identifying the group, as I only used that bit of preamble information once I had completed the grid as a final check.
On the other hand, is "modular arithmetic" (whatever that might be) within the level of expertise permitted? I must be getting very old :(

[williamjohn]

Any computer can find the last two digits of R^A etc. Square R, put the result as (integerx100 +two digit number) and square it again by binominal. Repeat again and again. Select results whose sum of indices equal A and multiply together.

[topa]

Now that the answer to 4270 has been published, it may be of interest to know that a friend of mine who is Swedish, living in Germany and therefore a little out of touch with St Andrew, managed to find a different theme, which worked ingeniously well, though not perfectly. Here’s his surprising take on it.

The dates are one date: 1212 2013, which is the date by which the solution is required. The two numbers forming the cross (following a supposed crossword theme) are: 4271, the number of the next puzzle and 4268, which is the number of the puzzle whose solution was expected to appear with it. 4271 appears as a V shape in the solution, and 2768 as an inverted V underneath it, forming a cross, fitting the cross (word) theme.
OK, “dates” does not carry the same meaning as “data” (being Swedish he thought the word might be able to be interpreted that way), and his theme doesn’t explain the puzzle title, but it’s interesting what patterns the human mind can find if it looks hard enough!