This Rare Friday the 13th

Juha-Matti Laurio writes to point out a Washington Times story about how special this particular Friday the 13th is. The digits in the numerical notation for the date add up to 13 — whether you write it in the US or the European form. From the article: "The phenomenon hasn't happened in 476 years, said Heinrich Hemme, a physicist at Germany's University of Aachen who crunched the numbers to find that the double-whammy last occurred Jan. 13, 1520."

Comments

How about something more interesting?

[winkydink]

Like it's the anniversary of the supposed origin of Friday the 13th being unlucky? October 13, 1307

self-promoting talking head?

[vague_ascetic]

"But it's not exactly TGIF for the 21 million Americans who fear the day. Some may not travel or even get out of bed, said Donald Dossey, a North Carolina psychologist who coined the term "paraskevidekatriaphobia" 20 years ago. He estimates that the nation is out $900 million in lost productivity because of Friday the 13th sick-outs."

How do they come up lost productivity statistics anyway?

Re:I Just Knew I Shoulda Stayed In Bed Today

[yo_tuco]

I wonder if Heinrich Hemme's calculations take into account the 10 missing days in the Gregorian calander between 4 October and 15 October 1582?

Re:Commutivity

[UglyTool]

*sigh*

1520 + 476 = 1996...

Re:Scheiße!

[Kredal]

Well, of course... because Dec 25 = Oct 31

(decimal and Octal, that is)

Knights Templar

[Danathar]

I find it funny that people regaurd today as unlucky when it's only the Aniversary of the sacking of the Knights Templar by the King of France and the Pope hundreds of years ago!

History that still effects people after so long is cool

I see it as lucky 7

[10e6Steve]

10-13-2006 would evaluate to 1 + 0 + (-1) + 3 + (-2) + 0 + 0 + 6 which equals lucky 7.

Re:A physicist?

[Iron Condor]

Here's a cute little first-year CS problem: show that with the current calendar the 13th of a month has a higher probability of falling on a friday than any other day of the week.

Playing with dates

[suso]

I was just playing around with cal, reading the man page and found this:


$ cal 9 1752
      September 1752
Su Mo Tu We Th Fr Sa
        1 2 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30


That's a really weird month. Appearently, the September Massacres happened on September 2nd, 1752. Don't know if there is a relationship there.

Also, I was playing with for loops, numsum, sed and such and came up with this list of years that also had Friday 13th in October and all the numbers added up to 13.

80
125
170
215
332
422
1133
1223
1340
1430
2006

I'm not sure whether this is accurate though with respect to the change from Julian to Gregorian calendars though. 2006 marks the 11th time this happened since the year 1. Interestingly, the 13th occurance of this will be in 2141, which is also the last one that will occur in the 3rd millinium. The 14th one doesn't occur until 3122 and there are only 20 of them total in the first 10,000 years. I guess they are pretty rare. My wife and I have actually found the number 13 to be lucky for us more than unlucky. But they are just numbers.

Re:I Just Knew I Shoulda Stayed In Bed Today

[ari_j]

The really interesting part of the switch, to me, is the Swedish debacle. Essentially, in 1700 they set a 40-year no-leap-days plan to get on track, but ended up with leap days in both of the following leap years, so they ended up one day ahead of the Julian calendar (and still nowhere near the Gregorian calendar). They held a February 30 double leap day in 1712 to get back on Julian and then finally managed to convert to Gregorian by 1753.

Re:I Just Knew I Shoulda Stayed In Bed Today

[Anonymous Coward]

Also, did you notice that the name of the shtml main page is 222223, which added is 13!