20221016, 18:52  #1244 
Jul 2003
Behind BB
2^{4}×3×41 Posts 
I listened to a Grateful Dead show for three hours last night ... great song!

20221218, 19:49  #1245 
"Reed Young"
Sep 2009
Oregon
1F_{16} Posts 
Given the standard definition of a prime...
Have you ever noticed, how the standard textual definition of a prime integer, taken literally, also includes all the perfect squares as well as perfect cubes and whatever hypergeometric terms would be used as analogy for the higher powers of each given prime number which has no divisors but 1 and arbitrarily many multiples of a single, other prime number? (for example 4, 8, 9, 16, 25, 27, 32, 49, etc.)
I know, I learned in elementary school that the perfect squares 4, 9, 16, 25, 49, etc. aren't really primes and we were taught that in such a way that 8, 16, 27, 32, 81, 125, etc. were so obviously not prime that nobody even asked. But as soon as this little irony occurred to me today, I searched the Internet to be sure I was remembering the "usual" definition right and sure enough, the definition that I see on the first few results is not quite the actual operational definition. The full definition in actual use but rarely if ever printed is, a number is prime if and only if it is divisible only by one and (only once) by itself. The bit in parentheses is usually omitted and if we take what is usually printed at face value, then 4, 8, 9, 16, 25, 27, 32, etc. are all prime! If this omission has negatively impacted anybody's mathematics education they haven't told me about it, and I don't suppose that's likely, as anybody who doesn't still recall that from their early math education is probably not a mathematician as an adult. I just find it interesting that people who talk about and work with prime numbers professionally take such a functionally relevant part of the definition for granted, and that it doesn't seem to cause even a hiccup. 
20221218, 20:03  #1246 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
89·113 Posts 

20221219, 05:29  #1247  
"Curtis"
Feb 2005
Riverside, CA
1011000000011_{2} Posts 
Quote:


20221219, 05:33  #1248 
If I May
"Chris Halsall"
Sep 2002
Barbados
2·7^{2}·113 Posts 

20221219, 11:03  #1249 
"Jacob"
Sep 2006
Brussels, Belgium
3×5×127 Posts 
Given the standard definition of a prime...
This kind of thing could happen when one gets so seduced by an idea, that one forgets the obvious : "a number is prime if and only if it is divisible only by one and by itself", the itselfpart has gone wrong in the presented reasoning.
But might it be that that was the intended joke ? The choice of thread should be a clue ;) 
20221220, 05:21  #1250 
"Reed Young"
Sep 2009
Oregon
31 Posts 
Yes, that's it exactly. I thought I had noticed something funny, not something mathematically relevant, and I rushed off to tell the joke without checking the math. Should have left the "have you ever noticed" schtick to Jerry Seinfeld.

20221229, 07:16  #1251 
"Matthew Anderson"
Dec 2010
Oregon, USA
2^{3}·149 Posts 
Did you see the new Star Wars movie?
Darth Vader gets married. … To Ella She becomes EllaVador She lifts him up. 
20221230, 02:48  #1252 
Aug 2002
North San Diego County
2^{2}·3·67 Posts 

20230117, 15:47  #1253 
Jul 2003
Behind BB
3660_{8} Posts 
What do you call a person without a body or a nose?
Nobody knows. 
20230117, 23:16  #1254 
Feb 2008
Meath, Ireland
185_{10} Posts 
Why won't Dijkstra create a sequel for Pokemon GO?
Because GO 2 considered harmful. 
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