# OK, maths wonks: PRIME TIME has arrived

Every Reg reader knows that a prime number is divisible only by one and itself. But did you also know that today is a big day for prime numbers? When the clock ticks over to 2:03:05 on November the 7th, 2013, the universe will experience an unusual alignment of prime numbers as the time becomes 02:03:05:07:11:13. Before you …

#### I hate to break it to you...

but 9 is not prime.

>"The alignment is not as propitious as that which took place on September 7th back in 2011, which sequenced the first six prime numbers at 02:03:05:07:09:11."

#### Re: I hate to break it to you...

You beat me to it...

And another thing, for the folks in some countries (who insist in using month/day/year format) this combination would have beeen 4 months ago. 02:03:05 07 (July) .11.13

#### Re: I hate to break it to you...

I was going to say they should have added the disclaimer that it only applies to 'Merkins not Brits, but you beat me to it.

The mayan calendar has been superceded by the oreo cookie ... It predicts many years of general yumminess.

Oreo's are horrible. Just more expensive Bourbon's with delusions of grandeur.

Bow down and all hail the mighty Jaffa Cake!!!!!!!

Oh dear. Double greengrocers' apostrophes in my post above. Shocking. Jaffa Cakes still rule though. I've got to go to the shops at lunchtime, now I'll have to buy some.

Yep, only 1g of fat per cake, so you can eat hundreds.

Don't count the sugar-based calories though, that will give you a heart attack (literally because the liver converts the sugar into fat).

If you mean the version of Jaffa cakes with orange filling that was so, and chocolate that not only tasted of chocolate, but snapped when being eaten then yes.

They predict that you're going to eat a yummy Jaffa Cake. What more could you need to know about your life?

How about doing it year/month/day, and adding a timezone...

13-11-07 05:03:02 UTC+01

in Central Europe today. Did anyone point this out 300 years ago, when we could have used the four-digit year:

1713-11-07 05:03:02 GMT+01

Because GMT was defined in 1675, UTC is a Jonny-come-lately from 1972.

1 was considered a prime in 1713, actually. But in 1913[*] it wasn't. Progress...

[* ] While 13, 17, and 19 are all primes, 1713 is not, but 1913 is - and it is only 100 year ago, not 300.

#### It is a lot more complicated than that.

http://mathworld.wolfram.com/PrimeNumber.html. The best part is how RSA patented two of the numbers.

Of course 1 is prime, and I always use it as q when I'm generating RSA key pairs (using it as p would be too obvious), because no-one else would think of doing that. Until now, Ooops!

#### If we're not using 1...

can I suggest

2357-11-13 17:19:23

as the last possible series of consecutive prime numbers without leading zeros packed into a valid datetime string. Only having 12 valid months makes it difficult to find other sequences.

> "Surely you don't consider 1 to be prime?"

What integer is it divisible by, other than one, and itself?

*" While 13, 17, and 19 are all primes, 1713 is not, but 1913 is - and it is only 100 year ago, not 300."*

I think his point wasn't that 1713 is prime, but 17 and 13 are, and work in the sequence of the first n primes.

#### Re: It is a lot more complicated than that.

Ha. Patenting the number is nothing. The US took crazy one step further by decreeing a prime (4856...[over 1,000 digits elided]...9443) illegal.

*What integer is it divisible by, other than one, and itself?*

To use the lingo, being divisible by no other number except 1 and itself is *necessary* but not *sufficient* to describe what a prime number is.

A prime number is divisible by 1 and itself only. So if 1 is not prime, every prime number is then divisible by a non-prime number. Hence ever prime number is not prime. Yeah, I'll go with that.

#### One hour at a time

So now we know it takes less than 60 minutes for the angels to wreak eternal vengeance, 'cos they have to be done in time to move on to the next time zone.

#### The sky fills with heavenly light when angels appear

It always does that when angels appear to me. Just saying.

#### Re: The sky fills with heavenly light when angels appear

Depends how many mushrooms you use

#### The end of an era is niegh

A great prime time! Sadly though I predict a drought of primal days. using day/month/year, December 28 is the last prime for the year (28122013). After that, there shall be no more primes days until 3/01/2017.

While I am not suggesting we stock-pile primes, I am alerting all to keep calm, carry on, and don't drink and derive.

#### Complete Bollocks

particulary as it's based on a time system based on Nailing people to Trees.

#### Re: Complete Bollocks

@AC more along the lines of giving birth to people in stables but thanks for the snark anyway.

#### The end of an era is niegh

A great prime time! Sadly though I predict a drought of primal days. using day/month/year, December 28 is the last prime for the year (28122013). After that, there shall be no more primes days until 3/01/2017. Right. No prime days for three years.

While I am not suggesting we stock=pile primes, and am alerting all to keep calm, carry on, and don't drink and derive.

#### Re: The end of an era is NEIGH surely?

What have horses got to do with it? Some posts on here are nigh on impossible to understand.

#### And for those that also miss the afternoon session...

...another chance in 13 days time, simply renounce the Gregorian calendar and switch back to Julian for the day.

#### Not prime, but...

Since we seem to have a lot of number-loving commentards (numeritards?) today, you may want to watch Prof. Hans Rosing on BBC 2 this evening. His take on statistics of any sort is guaranteed to be hugely entertaining:

http://www.bbc.co.uk/mediacentre/latestnews/2013/bbc-two-hans-rosling.html

#### Re: Not prime, but...

and let us not forget the excellent MoreOrLess podcast from BBC Radio 4, when it is on.....

P.

#### Re: Not prime, but...

*Since we seem to have a lot of number-loving commentards (numeritards?) today*

Or, as Moss from the IT crowd put it in the Countdown episode: "overnumerousness".

No 42 in there, so no worries (unless a Vogon constructor fleet appears (it's Thursday, after all))

#### the prime and year of !^^$

It was much earlier in at the time when they have decided about prime it was in 1664... Don't forget to drink for that in the Pub...

#### the prime and year of !^^$

It was much earlier in at the time when they have decided about prime it was in 1664... Don't forget to drink for that in the Pub...

#### Bah!

You forgot to mention you were using British date format too.

But then, it didn't work anyway so no harm no foul.

#### Unix time

Has prime number dates all the time: Since π(x) ~= x / ln x, just plug in Unix time (seconds since 1 Jan 1970) for midnight today and midnight tomorrow and subtract the two π(x) values. There are thousands of prime times each day.

#### Re: Unix time

43+ years of continuous clock time. They just don't make Operating Systems like they used to.