Six Nines in Pi

https://en.wikipedia.org/wiki/Six_nines_in_pi

by phonebucket • 7 years ago

60 39 7 years ago

en.wikipedia.org

nvusuvu• 7 years ago

I wonder what the longest known streak of identical digits is in pi. Also, does the sequence 0123456789 happen any in location of the known digits of pi?

hx2a2• 7 years ago

Using this website:

https://www.angio.net/pi/digits.html

I can search for the sequence 0123456789. It is not found in the first 200M digits.

dmurray• 7 years ago

There's a sequence of thirteen eights, and twelve of each of the other digits, documented at [0] which covers the first 2.7 trillion digits. Based on that you can be all but certain any given ten-digit sequence, including 0123456789, has also been found.

[0] https://bellard.org/pi/pi2700e9/pidigits.html

ksaj• 7 years ago

It surely does appear somewhere. But it isn't within the first 2 billion digits.

snagglegaggle• 7 years ago

Lo! Technology: https://www.angio.net/pi/

BlackLotus89• 7 years ago

17,387,594,880 http://mathworld.wolfram.com/PiDigits.html

klyrs• 7 years ago

I dunno about "known" but you can get a billion digits pretty easy.

  $ wget https://stuff.mit.edu/afs/sipb/contrib/pi/pi-billion.txt
  $ grep -ob 012345678 pi-billion.txt
  956753746:012345678
  $ grep -ob 0123456789 pi-billion.txt
  $

So close, and amusingly close to the end of the file!

hx2a2• 7 years ago

I love how Wikipedia contains these weird little nuggets of knowledge, and I love how they keep showing up on Hacker News.

vadansky• 7 years ago

Somewhat related:

https://github.com/philipl/pifs

If the expansion of pi is normal then all your data is already in it

0-_-0• 7 years ago

And you can compress any data as the index at which it occurs in pi!!!1!

jacobkg• 7 years ago

Can the index be reliably represented in fewer bytes than the data itself?

ashton314• 7 years ago

Is there a proof that says that any arbitrary finite sequence of digits will appear somewhere in the digits of pi? Are there finite sequences known to never appear?

marktani2• 7 years ago

Wow, your question led to some Wikipedia research on my end, and I found this:

'In particular, the popular claim "every string of numbers eventually occurs in π" has not been proven.'

I think I claimed this before. Oops!

Quote from https://en.m.wikipedia.org/wiki/Normal_number.

im3w1l• 7 years ago

It's a common misconception

ars• 7 years ago

See https://en.wikipedia.org/wiki/Normal_number Answer: No one knows, but we assume Pi is normal.

AlexCoventry• 7 years ago

The probability that that's the case is 1, but that's not the same as a proof.

nine_k• 7 years ago

Not in digits of pi necessarily (needs a proof), but indeed in any truly random character sequence with independent probabilities of characters; you can easily calculate the probability of it, exponentially decreasing with number of characters in the desired sequence.

jokoon• 7 years ago

would be cool to have the same thing for other bases

jeffwass• 7 years ago

I wondered the same thing, surprised it wasn’t mentioned in the Wikipedia article.

stOneskull• 7 years ago

Yeah. It doesn't seem like pi is meant to be base10

_bxg1• 7 years ago

This kind of trivia is my favorite thing to find on HN

sp3322• 7 years ago

The digits "360" are centered at the 360th digit. [Edit: if you include the leading 3 before the decimal, which Wikipedia doesn't.]

sp3322• 7 years ago

https://dilbert.com/strip/2001-10-25

marktani2• 7 years ago

These two belong together: https://xkcd.com/221/

Also really interesting to think about that you shared a comic that's almost 20 years old. Where did time go?

flatiron• 7 years ago

Sony did the same thing with the ps3

nategri• 7 years ago

Gets me thinking about then ending of the book version of Contact.

0xdeadbeefbabe• 7 years ago

A more numinous ending at that.

Aperocky• 7 years ago

All my passwords are conveniently stored in the constant Pi

hinkley2• 7 years ago

Now I'm adding √-1 to all my passwords.

codesushi42• 7 years ago

Now that's one complex password, I'd imagine.

gblanchette• 7 years ago

The first missing prime in the first million digits of pi is 100057 ( https://primes.utm.edu/curios/page.php?short=100057).

dvt• 7 years ago

Pi is conjectured[1], though not proved, to be normal. If true (likely), we can expect to find Moby Dick in its entirety somewhere in 𝛑, along with tomorrow's news of the day. Eventually, we'll find a string of digits nnnn....nnnn that's going to be longer than the number of particles in our universe. Of course, there's also a lot of gibberish.

[1] http://info.sjc.ox.ac.uk/users/gualtieri/Is%20Pi%20normal.ht...

happytoexplain• 7 years ago

Yes, there's no mathematical significance, but finding such a thing so early is emotionally intriguing to some humans, myself included.

dantondwa• 7 years ago

This reminds me of Borges' Library of Babel: https://libraryofbabel.info/libraryofbabel.html

8bitsrule• 7 years ago

The people who produced 800-1160-digit approximations of pi before computers ... back in the late 1940s (e.g. Wrench & Smith) ... used electro-mechanical calculators (e.g. Marchant). That (doomed) technology is well-documented here: http://www.vintagecalculators.com/

Six Nines in Pi

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