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Peyote

macrumors 6502a
Apr 11, 2002
760
1
The anniv date of my wife and I is New Years Eve, or 12/31, or 1231

So in the year 2023, our anniv date will be 123123

:)
 

MOFS

macrumors 65816
Feb 27, 2003
1,241
235
Durham, UK
feakbeak said:
A thread about numerical series and patterns... cool!

Here is one of my favorites.

1 + 3 = 4 (2^2)
1 + 3 + 5 = 9 (3^2)
1 + 3 + 5 + 7 = 16 (4^2)

In general, summing the first n odd numbers will always give you n^2. Very cool!

Actually isn't that (n+1)^2?! :D unless you count 1^2 = 1 as your first one?!

eg when n=4, it would be 1 + 3 + 5 +7 + 9 = 25 (5^2)
 

emw

macrumors G4
Aug 2, 2004
11,172
0
MOFS said:
Actually isn't that (n+1)^2?! :D unless you count 1^2 = 1 as your first one?!

eg when n=4, it would be 1 + 3 + 5 +7 + 9 = 25 (5^2)
No, he's right. In your example, n=5, not 4, since you have 5 odd numbers, not 4.

It works even if n=1, since the first n odd numbers =1, summed =1, and equals 1^2.
 

MOFS

macrumors 65816
Feb 27, 2003
1,241
235
Durham, UK
emw said:
No, he's right. In your example, n=5, not 4, since you have 5 odd numbers, not 4.

It works even if n=1, since the first n odd numbers =1, summed =1, and equals 1^2.

Actually, retrospectively, we're both right. In my case, n would be the number in the sequence ie 1) 1 + 3 = 2^2 (2) 1 + 3 + 5 = 3^2...(n) 1 + 3 + 5 +...+nth odd number = (nth odd number+1)^2. When n=9, the square is 100.

In your example, n=the number of odd numbers in the sequence ie when there are 9 numbers in the sequence n=9 and the square = 81.

More than one way to skin a cat! And cause maths confusion... :D
 

emw

macrumors G4
Aug 2, 2004
11,172
0
MOFS said:
Actually, retrospectively, we're both right. In my case, n would be the number in the sequence ie 1) 1 + 3 = 2^2 (2) 1 + 3 + 5 = 3^2...(n) 1 + 3 + 5 +...+nth odd number = (nth odd number+1)^2. When n=9, the square is 100.

In your example, n=the number of odd numbers in the sequence ie when there are 9 numbers in the sequence n=9 and the square = 81.

More than one way to skin a cat! And cause maths confusion... :D
Ah, yes. Thinking outside the box, I see! ;)
 

Doctor Q

Administrator
Original poster
Staff member
Sep 19, 2002
39,797
7,546
Los Angeles
Happy 5/5/5 and 05/05/05 and 050505 today!

Ahhh... a peaceful day when there will be no arguing over whether dates should be shown as day-month-year or month-day-year or year-month-day.

I find it interesting that most people are happy to write days and months with either one or two digits (05/05/05 or 5/5/05), but are so used to years with two digits that they are going to spend the whole decade writing the year as 05. Why not just 5? After all, you only need the zeroes if you are going to write 2005.
 

wdlove

macrumors P6
Oct 20, 2002
16,568
0
On our MBTA buses they list on the screen May 5, 2005 along with 5/5/5. So that they cover both angles. I was thinking about your number interest in another thread. Happy 5/5/5 to you also Doctor Q.

Sadly I missed it by one second of hitting the post at 5.5.55. :(
 

Awimoway

macrumors 68000
Sep 13, 2002
1,510
25
California
Doctor Q said:
I find it interesting that most people are happy to write days and months with either one or two digits (05/05/05 or 5/5/05), but are so used to years with two digits that they are going to spend the whole decade writing the year as 05. Why not just 5? After all, you only need the zeroes if you are going to write 2005.

I finally broke down this January (consider it a New Year's resolution), when the days and months went back to single digits, and began writing the year in single digit. So it took me half the decade to finally capitalize on this little productivity boost. To think of all those wasteful zeroes through the years...

Tragic.
 

TEG

macrumors 604
Jan 21, 2002
6,621
169
Langley, Washington
Awimoway said:
I finally broke down this January (consider it a New Year's resolution), when the days and months went back to single digits, and began writing the year in single digit. So it took me half the decade to finally capitalize on this little productivity boost. To think of all those wasteful zeroes through the years...

Tragic.

Funny,

I'm actually adding an extra zero on the years.

i.e. Today is 5-6/005

If we all did this, we wouldn't have to worry about resetting it until 3000.
Also, in two years we will all be living in 007.

TEG
 

Doctor Q

Administrator
Original poster
Staff member
Sep 19, 2002
39,797
7,546
Los Angeles
Wake up, ancient thread, wake up!

I hereby report that I celebrated the big moment yesterday when the date and time (in "sort" order) were 07 08 09 10:11:12.

I hope you all enjoyed it too! :)
 

rdowns

macrumors Penryn
Jul 11, 2003
27,397
12,521
This just made me LOL. Just what were you doing to celebrate at that moment? :D
 

Doctor Q

Administrator
Original poster
Staff member
Sep 19, 2002
39,797
7,546
Los Angeles
Yes, I counted from 7 to 12, but rather than increment by 1, I incremented by epsilon so it would takes longer to get to 12.

More counting = more fun. :D
 

Nermal

Moderator
Staff member
Dec 7, 2002
20,646
4,048
New Zealand
Thought you might appreciate this :)
 

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Queso

Suspended
Mar 4, 2006
11,821
8
Wake up, ancient thread, wake up!

I hereby report that I celebrated the big moment yesterday when the date and time (in "sort" order) were 07 08 09 10:11:12.

I hope you all enjoyed it too! :)
I have to confess I noticed it too :eek:
 

Doctor Q

Administrator
Original poster
Staff member
Sep 19, 2002
39,797
7,546
Los Angeles
123 123

Many couples in the U.S. are getting married tomorrow because the date is 12-31-23, aka 123-123. That's another great date pattern to add to our list. If you want to get married tomorrow, you'd better get planning right now! (And if you're already married, you'll have to get a quickie divorce today in order to get re-married tomorrow.)

In RFC 822 format, but with a 2-digit year, tomorrow is 23-12-31 or 231-231, another repeated 3-digit pattern.

By European conventions it's a less interesting date, 31-12-23 or 311-223. Europeans had a more entertaning date ten years and one month ago, when it was the palindromic date 31-11-13, or 311-113.

Regarding American m/d/y format versus European d/m/y format, something occurs to me. The European format, with the least significant number first, has always made more logical sense than the American format, with the least significant number in the middle, yet both Americans and Europeans use the American order for personal names. Shouldn't we refer to Paul Steven Jobs instead of Steven Paul Jobs?
 
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