Programming Challenge: Find a Particular Prime Number - Printable Version +- HP Forums ( https://www.hpmuseum.org/forum)+-- Forum: HP Calculators (and very old HP Computers) ( /forum-3.html)+--- Forum: General Forum ( /forum-4.html)+--- Thread: Programming Challenge: Find a Particular Prime Number ( /thread-7123.html)Pages: 1 2 |

Programming Challenge: Find a Particular Prime Number - Gerald H - 10-29-2016 11:31 AM
Using any HP calculator, find the alphabetically first prime number as written in Standard German orthography.(Not English as there are too many variations in USA, UK, etc) Programme & solutions please. RE: Programming Challenge: Find a Particular Prime Number - Maximilian Hohmann - 10-29-2016 11:58 AM
Hello! Maybe I don't understand the challenge, but my solution would be something like: *deleted* ... I finally understood what it is about. I think know the solution without writing a program (which would not fit into my favorite progammable calculator, the Hp25, anyway). Regards Max RE: Programming Challenge: Find a Particular Prime Number - Thomas Okken - 10-29-2016 02:10 PM
acht Billiarden acht Billionen achthundertdreiundzwanzig EDIT: Oops, no: acht Billiarden acht Billionen achthundertdreiundvierzig RE: Programming Challenge: Find a Particular Prime Number - Maximilian Hohmann - 10-29-2016 02:26 PM
(10-29-2016 02:10 PM)Thomas Okken Wrote: acht Billiarden acht Billionen achthundertdreiundvierzig acht Billiarden acht Billionen achthundertachtzigtausendhundertneunzehn (I used this generator for the primes: https://www.browserling.com/tools/prime-numbers and this converter to get the german words: http://bmanolov.free.fr/num2textconv.php) RE: Programming Challenge: Find a Particular Prime Number - Thomas Okken - 10-29-2016 02:52 PM
(10-29-2016 02:26 PM)Maximilian Hohmann Wrote: acht Billiarden acht Billionen achthundertachtzigtausendhundertneunzehn Nice!! I arrived at the "acht Billiarden acht Billionen achthundertdreiund-" part by reasoning, but I goofed in missing the fact that you can tack on another "acht" after the "hundert" (i.e. that the "achthundert" could be 800000 instead of 800). I used this to check primality: https://www.alpertron.com.ar/ECM.HTM RE: Programming Challenge: Find a Particular Prime Number - Thomas Okken - 10-29-2016 03:05 PM
acht Billiarden acht Billionen achthundertachtzigtausendachthundertdreiundsechzig RE: Programming Challenge: Find a Particular Prime Number - Maximilian Hohmann - 10-29-2016 05:20 PM
(10-29-2016 03:05 PM)Thomas Okken Wrote: acht Billiarden acht Billionen achthundertachtzigtausendachthundertdreiundsechzig Cool! Like you, it figured out quickly that "acht Billiarden" must be the starting point. Next, I came to the conclusion that I only have very few calculators in my collection which might me capable of testing if such large integers are primes, converting the numbers to strings and storing and sorting those strings. And all in a survivable timespan... The Hp50, Ti89/200, HP71B and a couple of other BASIC programmables maybe. Looking forward to see some actual programs running on a calculator! Max RE: Programming Challenge: Find a Particular Prime Number - Thomas Okken - 10-29-2016 06:39 PM
Yes, the search space is too large for pure brute-force, and once you start thinking about how to reduce it, before you know it you've solved the puzzle by reasoning alone -- although we both demonstrated how easily you can get that wrong. :-) I thought this might be a puzzle that others had figured out and written about before this, but all I found was this: http://www.matheboard.de/archive/547281/thread.html RE: Programming Challenge: Find a Particular Prime Number - Thomas Okken - 10-30-2016 05:15 PM
acht Billiarden acht Billionen achthundertachttausendachthundertdreiunddreißig RE: Programming Challenge: Find a Particular Prime Number - Gerald H - 10-30-2016 10:00 PM
If you allow "Billiarde" & "Billion" I guess you have also to allow "Milliarde" & "Million"? RE: Programming Challenge: Find a Particular Prime Number - Maximilian Hohmann - 10-30-2016 10:33 PM
(10-30-2016 10:00 PM)Gerald H Wrote: If you allow "Billiarde" & "Billion" I guess you have also to allow "Milliarde" & "Million"? Sure. But that doesn't help in this specific puzzle! RE: Programming Challenge: Find a Particular Prime Number - Thomas Okken - 10-31-2016 01:53 AM
This is what I come up with when trying to enumerate numbers in German alphabetical order: acht acht Billiarden acht Billiarden acht acht Billiarden acht Billionen acht Billiarden acht Billionen acht acht Billiarden acht Billionen achthundert acht Billiarden acht Billionen achthundertacht acht Billiarden acht Billionen achthundertachttausend acht Billiarden acht Billionen achthundertachttausendacht acht Billiarden acht Billionen achthundertachttausendachthundert acht Billiarden acht Billionen achthundertachttausendachthundertacht acht Billiarden acht Billionen achthundertachttausendachthundertachtundachtzig acht Billiarden acht Billionen achthundertachttausendachthundertachtunddreißig acht Billiarden acht Billionen achthundertachttausendachthundertachtundfünfzig acht Billiarden acht Billionen achthundertachttausendachthundertachtundneunzig acht Billiarden acht Billionen achthundertachttausendachthundertachtundsechzig acht Billiarden acht Billionen achthundertachttausendachthundertachtundsiebzig acht Billiarden acht Billionen achthundertachttausendachthundertachtundvierzig acht Billiarden acht Billionen achthundertachttausendachthundertachtundzwanzig acht Billiarden acht Billionen achthundertachttausendachthundertachtzehn acht Billiarden acht Billionen achthundertachttausendachthundertachtzig acht Billiarden acht Billionen achthundertachttausendachthundertdrei <- first odd number acht Billiarden acht Billionen achthundertachttausendachthundertdreißig acht Billiarden acht Billionen achthundertachttausendachthundertdreiundachtzig acht Billiarden acht Billionen achthundertachttausendachthundertdreiunddreißig <- first prime number It looks like the real challenge of this puzzle is enumerating numbers in alphabetical order. I bet it's not too much harder to do this in English. :-) RE: Programming Challenge: Find a Particular Prime Number - Thomas Okken - 10-31-2016 03:26 AM
eight eight billion eight billion eight eight billion eighteen eight billion eighteen hundred eight billion eighteen hundred eight eight billion eighteen hundred eighteen eight billion eighteen hundred eighty eight billion eighteen hundred eighty-eight eight billion eighteen hundred eighty-five <- first odd number eight billion eighteen hundred eighty-four eight billion eighteen hundred eighty-nine eight billion eighteen hundred eighty-one <- first prime RE: Programming Challenge: Find a Particular Prime Number - Paul Dale - 10-31-2016 03:49 AM
(10-31-2016 01:53 AM)Thomas Okken Wrote: I bet it's not too much harder to do this in English. :-) The problems will arise due to different flavours of English having different rules for numbers. e.g. eight billion and nine is prime, although some folks wouldn't agree either on primality or the English used. I doubt it is the first. Is a billion 1,000,000,000,000 or merely 1,000,000,000 ? Is it three hundred two vs three hundred and two. Pauli RE: Programming Challenge: Find a Particular Prime Number - Thomas Okken - 10-31-2016 11:37 AM
I didn't realize that "billion" still means 10^12 in (any parts of) the English-speaking world! Do those dialects also still use "milliard" etc.? Allowing the word "and" doesn't change things, though: "eight billion and eighteen hundred eighty-one." Unless there are rules about where exactly "and" is or isn't allowed in a number, and as a non-native speaker, I have nothing to contribute to that discussion. :-) RE: Programming Challenge: Find a Particular Prime Number - Gerald H - 10-31-2016 04:02 PM
English was excluded in Post #1 due to variations between the lesser billion & the greater billion (although one billion two hundred & seventy-one is prime both ways) & deviant usage of "and" in US & UK. Normatively in UK "and" is inserted between hundreds & smaller numbers. Expressions such as "eighteen hundred" are not regularly used inside larger numbers & , except for year numbers, are more for colloquial style. In counting objects the form is rarely used. German usage is in general better standardized. My own preference is to avoid using the b-numbers due to 1 Ambiguity amongst English speakers 2 Ignorance among all speakers. In a survey in Vienna the majority could not read 1,345,000,222,000 as a number containing the word "Billion". Avoiding b-numbers, I was originally happy to consider 883 the solution to the challenge. As Duden recognizes b-numbers I acknowledge Thomas Okken's suggestion as preceding 883 alphabetically & a more worthy candidate to win the challenge. I trust seekers are trying to find an alphabetically prior solution. RE: Programming Challenge: Find a Particular Prime Number - Thomas Okken - 11-01-2016 05:17 AM
If you want to exclude Billiarde and Billion (or if you want to exclude all solutions that consist of multiple words) then the answer is 808853. I'm not surprised that people in Vienna don't read a 13-digit number as something containing the word "Billion." I read German-language news every day, and the word Billion shows up very rarely. Millionen and Milliarden, yes, but Billionen, not so much. RE: Programming Challenge: Find a Particular Prime Number - Gerald H - 11-01-2016 06:38 AM
Touché, Thomas Okken, without b-numbers & m-numbers 808853 wins. & with b-numbers & m-numbers? RE: Programming Challenge: Find a Particular Prime Number - Maximilian Hohmann - 11-01-2016 11:44 AM
Hello! (11-01-2016 05:17 AM)Thomas Okken Wrote: I read German-language news every day, and the word Billion shows up very rarely. If you read the finacial part of the newspaper the billion comes up quite frequently, mostly in conjunction with the U.S. state deficit... Regarding a solution for the Billiarde/Billion case that can be implemented on a pocket calculator, I still dont't have the faintest idea how that could possibly work. Regards Max RE: Programming Challenge: Find a Particular Prime Number - Thomas Okken - 11-01-2016 01:19 PM
(11-01-2016 06:38 AM)Gerald H Wrote: & with b-numbers & m-numbers? In that case, my earlier submission still stands: 8,008,000,000,808,833. That was composed assuming no restrictions on allowable words. |