Math Quirks:...Anybody (else) experienced strange Date coincidences ?

[TimFox]

The Ides of March is actually March 15.
The Ides of March, May, July, and October are on the 15th, the other months have Ides on the 13th, in the old Roman calendar.
The Nones of each month are 8 days earlier than the Ides.
The Kalends of each month are the 1st of the following month, just to confuse people.

[helius]

Thanks for the correction!
In addition, the Romans considered each day to begin and end at noon instead of at midnight.

[TimFox]

Noon is much easier to determine than midnight.

[RJSV]

I love it when one of these number quirks / anomalies contain a partial language component, like the conversion of October to mean octal code, and of December to the decimal mode identifier.   Somewhat classified in the 'PUN' catagory.   (Seen a few posts back.)

   Of course, I should have anticipated that many of the responses here are calendar related.

[Nominal Animal]

Noon is much easier to determine than midnight.

Icelandic vikings at least seem to have used "sunstones", cordierite or iceland spar, to detect the direction (azimuth) of the sun even in overcast weather.  Not just on sea voyages, but in everyday life, to check the time of day.

Many of the daily aspects of even Roman life have been forgotten.  For example, why did they carry those dodecahedra around in second to fourth century CE?

[TimFox]

The noon start persists in modern language:  AM and PM abbreviations mean "before noon" and "after noon" (not midnight) in Latin.
Latin:  "ante meridiem" and "post meridiem"  ("antemeridian", a rare word sometimes misused, means "of or belonging to the morning")

[RJSV]

   Actually, (thanks Helius),  the slang term '420' had it's origins in the police radio code chatter, which, if I'm to believe the common folk-story, the '420' was the code number for
   'Cannabis smoking taking place', as the illegal activity to respond to.

   However, I'm not sure what is the term to use, for some social assumption, commonly believed, or non-scientific fact being stated.  Those type statements are difficult to track or verify directly...(maybe I should start by checking out what Wikipedia says.)
Now, if you read, someplace, that Marijuana was discovered by Bob Marley, THEN I'd be assuming that's just an old rumour.

[TimFox]

One possibility for "the term to use, for some social assumption, commonly believed, or non-scientific fact being stated" is "urban legend", originally applied to lurid stories heard from a "friend of a friend".
https://www.dictionary.com/browse/urban-legend

[RJSV]

Yes, thanks Tim:
   It's a small diversion from topic, but I noticed I had difficulty fumbling for the appropriate terms, when discussing non-scientific labels, but you have similar approach:
   Wiki, and other sources use phrases like 'Some say...' or 'Common belief is....' without delving into rigorous proof.  Of course that creates a lot of wiggle room for creative manipulations, but that can happen also with 'Urban Myth' types of Meta-descriptors.
   Did I just create a novel word combo ?

[TimFox]

You might be interested in G Flaubert's  Dictionary of Accepted Ideas  https://archive.org/details/gustave-flaubert-dictionary-of-accepted-ideas-barzun
Many of those ideas are actually true.

[helius]

Phrases like "some say" are known as weasel words because they are irrefutable.
The idea put forth may still be true, but it provides no basis for believing it so.

[RJSV]

...Yes but WEASLE words accurately describes the setting, that is of a sort of 'common understood' to the degree that, for example, you could state:
   "All my cousin's friends keep saying they think my singing is professional."

   This the WEASLE word is, ironically, a definite term, (while describing an indefinite situation).

At the end of the day, there's got to be some technical language term or word for this.

Like, anachronism or some such wordy word.  Some non-science conclusion about meaning of some word, or term, that's more by (social) consensus.

[RJSV]

   At any rate, back to more MATH
or calendar  related coincidences, one date I've seen is Jan. 25.
If you take that date it's 1-25 or simply 125.  Now, that's a perfect CUBE, of 5.  I'm not going into the personal history of that, right now, but it's been 'a presence', such as a business street address.
Even better, that address is actually '25125'  and thats a massively ironic number!
I mean; you've got 5 squared, 5 cubed, and a little bonus in that the '125' portion has the cube value containing the squared value....That would be similar to something like:
   '1664' where you have 4 squared and 4 cubed...but notice, however, THIS time we don't get that '64' as containing a '16', like the '125' contains (contains 25).

   Seems maybe obsessive, but have to admit that 5 in this process has the special quality that using '4' doesn't, which brings up the question, of Where the specials are?...or is this self referenced only for when using integer '5' to square and cube.
By themselves these effects are merely interesting, but when living and working under such 'magic' numbers can be interesting to greater effect....a louder Wow factor, (I suppose).
Enjoy

[RJSV]

...oh yeah, I also forgot to mention........wait for it......
   Office number is 'Suite #5', there, (or actually distantly associated but close enough to notice)

Also, (at the moment expense of possibly boring the reader, lol,),
   Notice the '125' is very close to saying 1/2 of 25 is 12.5   So readers can see how fluid the process is, of associating seemingly random bits of random English into the numbers.

[RJSV]

   So, round and round this quirky process goes!  It can get to be a vanity, with all the self-attention from Numerology.
   Now that I'm on a roll, might as well get into some additional 'Squares', in the form of 12 squared, '144'.
Notice, that seems to be sneaking up on my original '1440' address mentioned at thread start.
Then, #169....that's 13 squared (this is getting easy).  But that storage unit number shows itself, to the degree where I had started to look;  Where is (my) 14 squared, then ?  Haven't seen it, but that comes to 196.  When I have some more time, or see another route to coincidence, I can tackle decode that one.

   Maybe I should post a contest, Lol.

[RJSV]

   First 100 digits of PI:
   Interesting, this contains '1971'  and a couple, '2089' and one other '20xx',  (plus I don't have time of birth).  Must go to 1000 digits, to get more relevant results.

[helius]

At the end of the day, there's got to be some technical language term or word for this.

Like, anachronism or some such wordy word.  Some non-science conclusion about meaning of some word, or term, that's more by (social) consensus.

A term or phrase used outside of its consensual meaning is called a solecism. All you need is an antonym of that.

edit: "relevant results"? You do realize that the expansion of pi contains every possible subsequence?

[RJSV]

No, I hadn't realized the fuller aspect, of finding literally anything, any sequence of digits.
   Which brings up a question about books, do you know of a good book or two that has focus on PI and some historical stuff ?   Of course, I'll have to do web search on books, thanks.

[RJSV]

   I forgot to put in reply, that how much of this thread involves language, and even edging into ironic 'puns'.  That is treating numbers, in singular isolation, and in subgroups.  BTW one of my favorite things is to regard digit sequences backwards or forwards.  Thus an area code, like (494) can be instantly considered to contain '49' twice; meaning once left-to-right and once right-to-left (looks like '94').

That '49' by the way, is (effortlessly) an old, established reference, to Grass Valley, CA and Nevada City from the GOLD RUSH era around 1850's !

[helius]

Not a book about π specifically, but I do have some interesting math (history) books.

Prime Obsession by John Derbyshire, ISBN 0-309-08549-7
Gamma by Julian Havil, ISBN 0-691-09983-9
The Monty Hall Problem by Jason Rosenhouse, ISBN 978-0-19-536789-8
The Annotated Turing by Charles Petzold
What is Mathematics? by Herbert Robbins (credited to his boss, Richard Courant)
(can't find the latter two so no ISBN)

I was given Fermat's Enigma but found it disappointing. Barely any mathematical content at all, on the level of "A Beautiful Mind".

[TimFox]

A wonderful interesting recent novel about nothing, words, logic, and mathematics:  "Dr No" by Percival Everett (without so much Ursula Andress)  https://www.influxpress.com/dr-no

[RJSV]

   I glanced at that book review, 'Dr. NO', thanks.
Not sure your drift, if it's subtle, but yes, this thread about seemingly unrelated numerical structures can have a feel of being, maybe frivolous.   That so because (we are) maybe chasing some aspects that have no apparent, clear goal or outcome, aside from some immediate little 'aha' moment when a couple of items match up.
    Humans have long history of 'pondering' things and processes that contain clues of mysterious relation.  Maybe a couple of relatives had died, on the same day of the month, or same holiday.  But where (those) little 'drama' paths lead isn't clear, besides having a good grasp of coincidences in the statistical sense.  In fact, a little investigation may prove that, for example, a person should not, rationally be nervous when a third occurrence of a 'friday 13th' comes along, and recognition that coincidence won't 'cause' yet another relative to pass.  I get that.

   But, I'm saying we could still look at things, maybe just for frivolous entertainment, then, as various combinations of addresses, dates and times, and even quirky word play pass by, as world turns under our noses.  Next, here is my latest example (fictional):

   Is there a radio talk code for 'NO VISABILITY' sky or cloud conditions ?  Like "We got a '409' going on along the coast".  (A totally made up example).
Then, there is a blind fellow, 'Hector',  who has been living in a cottage there, at '409 Jackson St.'

Coincidence ??    Probably, 99.9 %

[RJSV]

LOL, I looked up some various radio (police) codes and, right away there are verbal codes for 'weather conditions', I think it said '10 - 25' or similar.  The code '10 - 4' means acknowledgement, msg received.

   BUT THEN, further down the list was '10 - 20', one of my (all-time) favorite numbers!  THAT was my first office address, as a 'professional' inventor, and overall unemployed 'dead-beat', having no tangible success to show, other than interesting stories to relate....

   Meaning of radio code '10 - 20' is 'LOCATION'...as in, in my case;

   "My, uh, '10 - 20' is 1020.".         That had been '1020 D St. Hayward, CA'

Post Script:    that's 17 X 6,  X 10,  for anyone interested in '17' action.

[Circlotron]

https://bluewatercredit.com/random-event-generators-predict-911-attacks-world-events-tune-princetons-global-consciousness-project-find/

[DavidAlfa]

I very often have a peek at the clock and catch 12:12, it must be a Final Destiny thing.