Prime Directive ?

31 prime
By pgn
@pgntwo (21552)
Derry, Northern Ireland
May 17, 2017 3:06pm CST
Here's one for the mathematicians amongst us. Most people know that a prime number is only divisible by itself or by 1, for example, the number "31". So if you keep placing a 3 in front of 31, (331; 3,331; 33,331...), it stays prime until it reaches 333,333,331 (which factors into 19,607,843 x 17). Why is that, I wonder...? PS. I tested out some of the possibilities on WolframAlpha, a mathematical search engine, adding or removing a 3 each time:
To see full output on this page you need to enable JavaScript in your browser. Computing... Input: Result: Computing... Give us feedback » Computed by Wolfram Mathematica View Wolfram|Alpha in:  Mobile  |  Standard © 2017 Wolfram Alpha LLC Terms of Use  | 
16 people like this
16 responses
@xFiacre (4278)
• Ireland
17 May 17
@pgntwo This is why I always insisted that my kids learn their 17 times tables.
5 people like this
@pgntwo (21552)
• Derry, Northern Ireland
17 May 17
Did it help?
3 people like this
@xFiacre (4278)
• Ireland
17 May 17
@pgntwo only when asked what 333333331 was divisible by.
3 people like this
@pgntwo (21552)
• Derry, Northern Ireland
17 May 17
@xFiacre Something is innately wrong with the world, I can't quite put my finger on it...
1 person likes this
• Preston, England
18 May 17
@pgntwo maths usually causes my mind to disintegrate
4 people like this
@pgntwo (21552)
• Derry, Northern Ireland
18 May 17
It has that effect on many, alas. Me included.
3 people like this
@LadyDuck (147879)
• Switzerland
18 May 17
I hate maths, when I see a number I turn my head in another direction. I do not know the answer and I do not care to know.
3 people like this
@pgntwo (21552)
• Derry, Northern Ireland
18 May 17
Ah, a numerohobe, or an arithmophobe?
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3 people like this
@LadyDuck (147879)
• Switzerland
19 May 17
@pgntwo BOTH! Finally is the same think because the Greek arithmos means 'number'.
1 person likes this
@pgntwo (21552)
• Derry, Northern Ireland
19 May 17
@LadyDuck Those Romans and Greeks, eh?
1 person likes this
• Peoria, Arizona
17 May 17
I feel like someone has to be very bored to figure that out haha! But interesting nonetheless!
3 people like this
@pgntwo (21552)
• Derry, Northern Ireland
17 May 17
Such is the way of idle hands, an inquiring mind and a handy calculator...
1 person likes this
• Peoria, Arizona
24 May 17
@pgntwo Apparently so!
1 person likes this
18 May 17
I'm afraid that I completely switched off when you mentioned the word mathematician. *makes the sign of the cross*
3 people like this
@pgntwo (21552)
• Derry, Northern Ireland
18 May 17
It is amazing how often people subconsciously make a depiction on their upper torso of a structure consisting of an upright with a transverse beam...
1 person likes this
@JudyEv (119003)
• Bunbury, Australia
18 May 17
Good one. A worthy post for a site about numbers rather than words. Do you remember the discussion about that?
3 people like this
@pgntwo (21552)
• Derry, Northern Ireland
18 May 17
I most definitely do, that is what made me think of sharing a discussion I had had with a friend last week...
3 people like this
@DWDavis (10774)
• Pikeville, North Carolina
17 May 17
It's all part of the grand design to keep us guessing.
3 people like this
@pgntwo (21552)
• Derry, Northern Ireland
17 May 17
And there was me thinking it was chance...
3 people like this
@MALUSE (38064)
• Germany
17 May 17
This is beyond my intellectual capabilities.
3 people like this
@pgntwo (21552)
• Derry, Northern Ireland
17 May 17
And not something easily discovered using a search engine, it seems, @MALUSE. Who says myLot is purely a textual medium?
1 person likes this
@YrNemo (11188)
21 May 17
This is very interesting! (I am going to tease some kids about this.)
2 people like this
@pgntwo (21552)
• Derry, Northern Ireland
21 May 17
Be prepared for a shrug of the shoulders and a "so what?"
1 person likes this
@YrNemo (11188)
21 May 17
1 person likes this
@Susan2015 (20190)
• United States
20 May 17
Math was my absolute worst subject in school.
2 people like this
@pgntwo (21552)
• Derry, Northern Ireland
21 May 17
My appreciation for the subject grew after I left school. Not enough to be a boffin though, calculators and spreadsheets help.
2 people like this
@Susan2015 (20190)
• United States
21 May 17
@pgntwo Yes they sure do.
1 person likes this
@sishy7 (27666)
• Australia
21 May 17
how so very interesting! I didn't know that and I find it fascinating just like all of the other facts about maths and numbers.
1 person likes this
@pgntwo (21552)
• Derry, Northern Ireland
21 May 17
You are probably the first - most other comments are how numbers are scary...
1 person likes this
@sishy7 (27666)
• Australia
21 May 17
@pgntwo I find it so interesting too how it continues to be non prime as we keep placing a 3 in front of 333,333,331.
1 person likes this
@pgntwo (21552)
• Derry, Northern Ireland
21 May 17
@sishy7 I thought so too, until I ran out of compute power to determine if being prime applied for 33,333,333,333,331...
1 person likes this
@DaddyEvil (23552)
• Aurora, Missouri
20 May 17
Hmmm... I am nowhere close to a mathematician, pgn... (I'm lucky I know what a prime number is, let alone most things involving math!) Yes, I can add, subtract, multiply and divide in my head quite quickly, but you really should talk with @sishy7 about things like this! LOL!
1 person likes this
@pgntwo (21552)
• Derry, Northern Ireland
20 May 17
Mathematicians, accountants, economists - the world is in the state it is because of 'em, I think.
1 person likes this
@DaddyEvil (23552)
• Aurora, Missouri
21 May 17
@pgntwo Hmmm... not sure about that, pgn... maybe just the greedy people who hire them!
2 people like this
@pgntwo (21552)
• Derry, Northern Ireland
21 May 17
@DaddyEvil It could be - but the controllers must be hot with numbers too, I'd guess.
1 person likes this
@much2say (38752)
• United States
17 May 17
My daughter has recently had to deal with good 'ol prime numbers and factoring in her math class . . . math makes her head hurt as much as it does mine (especially the way they teach it these days ). I wonder if her teacher knows about this one .
1 person likes this
@pgntwo (21552)
• Derry, Northern Ireland
17 May 17
Be worth a brief note, you never know what it might turn up...
1 person likes this
@much2say (38752)
• United States
19 May 17
@pgntwo I'll save the note for her next math teacher . . . this one is too serious and not too personal with personal notes.
1 person likes this
@pgntwo (21552)
• Derry, Northern Ireland
19 May 17
@much2say Probably wise. We had a physics teacher who could very easily be diverted down a different path from the day's lesson plan, if the right topic was brought up by one of his students.
1 person likes this
@Mike197602 (13363)
• Worcester, England
17 May 17
I got a few A's in GCSE's and A levels...maths was not among the A's PS...this discussion reminded me of Optimus Prime from the transformers...when pissed I look at his end speech from the film on youtube
The final scene from the first Transformers movie.
1 person likes this
@pgntwo (21552)
• Derry, Northern Ireland
17 May 17
I'm going to have a listen to that later, I just know it... And yeah, maths was not my strong point, either.
1 person likes this
@Mike197602 (13363)
• Worcester, England
17 May 17
@pgntwo I like the linkin park track and I'm a fan of the megan fox/shia lebouf, or whatever his name is, films.
3 people like this
@Mike197602 (13363)
• Worcester, England
17 May 17
The link is there...it is waiting
3 people like this
@CRK109 (14419)
• United States
21 May 17
I have never truly understood Math and I'm sure math has never truly understood me.
1 person likes this
@pgntwo (21552)
• Derry, Northern Ireland
21 May 17
Seems to be a common theme on this discussion thread, not many admit to liking the subject. Ah well.
1 person likes this
@CRK109 (14419)
• United States
21 May 17
@pgntwo I'm not sure that writing and math go hand in hand all that often. My late husband loved math! And I forgave him for that.
1 person likes this
@valmnz (12638)
• New Zealand
18 May 17
I'm just going to have to believe you!
1 person likes this
@pgntwo (21552)
• Derry, Northern Ireland
18 May 17
I had a play with this number series on the mathematical search engine, WolframAlpha, here's a sample - add or remove 3s until it starts to be "not prime":
To see full output on this page you need to enable JavaScript in your browser. Computing... Input: Result: Computing... Give us feedback » Computed by Wolfram Mathematica View Wolfram|Alpha in:  Mobile  |  Standard © 2017 Wolfram Alpha LLC Terms of Use  | 
1 person likes this