## Thursday, June 18, 2009

### 142857 is an Interesting Number

A couple of days ago a colleague sent me this interesting number, 142857, via email. I performed a Google search on the number and I was surprised to see so many returns - 190,000. It even has its own wiki page. For additional information, here is the wiki page for this cyclic number - 142857.

Below is the email.

Subject: Interesting Numbers

Roy,

I want to let you know a weird number which is 142857.

Why?

142857 X 1 = 142857
142857 X 2 = 285714
142857 X 3 = 428571
142857 X 4 = 571428
142857 X 5 = 714285
142857 X 6 = 857142

See, the answers show all same numbers with different position.

142857 X 7 = 999999

142 + 857 = 999
14 + 28 + 57 = 99

142857 X 142857 = 20408122449
20408 + 122449 = 142857

Interesting, huh?

#### 11 comments:

bogdan said...

Really nice numbers. But maths have fascinating things if you search for them.

Unknown said...

You're right bogdan, math is very fascinating and pure

kemitche said...

1/7 = 0.142857 (repeating)
Which "explains" some of the interesting facets of that number. It's still fascinating that 1/7 would be so cyclical, though.

Chris said...

Cool! interesting stuff!

vdsAdmin said...

WOW.. ! very interesting ! this is a magic number !)
Thanks..

fan of subscribemonkey said...

i love your blog dont stop blogging

http://www.youtube.com/subscribemonkey

pp said...

i was going through divisions of 360 and got curious about 360/7=51.(428571)

since dividing 360 by any other number from 1 to 10 besides 7, i started wondering if this could be related to a "higher 'dimensional' oddity"

since string theory uses 10+16 dimensions for ((3+1)+6)+16 i ran a few quick caluclations using base-16 instead of base-10, and lo and behold:

360(DEC)=168(HEX)
168/7=33

22(DEC)=16(HEX)
16/7=3

probably just us humans picking the "wrong" base (10) to describe a reality which is of 10+16=26 dimension

360(DEC)=DM(base-26)
DM/7=1P

pp said...

disregard my comment, my calculator lied to me when it stated it could to decimals in any base *sigh*

unix.systems.administrator said...

That number sticks out to me. That was the only question that I failed in a technical interview for a job with google. I could not figure out for the life of me why the interviewer asked me that question. It sort of makes sense based on the job that I was going to be doing or perhaps it was the endeavor of a very sick interviewer?

Anyway, your posting did explain things better.

cubefeed
Unix/Linux Systems Administrator Resource

Unknown said...

cubefeed,

That's interesting that Google asked you about that particular question during the interview.

At any rate, did you get the job?

unix.systems.administrator said...

No, I didnt get the job. That was the only question in the interview that I didnt answer correctly.

Incidentally, after spreading the word to other sysadmins, I am not the only person to go through this with this same group at google.

I wish someone before me had spread the word. Oh, well....

Cubefeed
Unix/Linux Systems Administrator Resources