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Journal of No. 118


September 26th, 2008

Prime time for Oktoberfest @ 02:13 pm

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USC lost to the Ducks got licked by the Beavers and UCLA discovers the largest known Mersenne prime.

Mersenne primes, you'll recall, are those in the form (2^p) - 1, where p is itself prime.

When p=2, you get 2^2 - 1 = 3, which is prime
When p=3, you get 2^3 - 1 = 7, which is prime
When p=5, you get 2^5 - 1 = 31, which is prime
When p=7, you get 2^7 - 1 = 127, which is prime

Seems like a pattern is forming, but with p=11, you get 2047, which is obviously 23 x 89, i.e. not a prime.

This new prime is only the 46th Mersenne prime known. I would be hard-pressed to show that 43,112,609 is prime, but this new one is 2^43,112,609 - 1, a number with nearly 13 million digits.


Oktoberfest in Munich seems to be changing for the better, as if that were possible.

Speaking of which, Chalet Edelweiss now seems to be open for business, although there's still some odd construction material about. The menu doesn't thrill me, but German beer on tap calls to me.
 
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From:gotham_bound
Date:September 26th, 2008 09:51 pm (UTC)
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Psht. OSU are the Beavers. Shows how much you know.


*returns to licking wounds*
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From:ningwers
Date:September 26th, 2008 09:59 pm (UTC)
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As anyone from the northwest will tell you is an important distinction. The Ducks (and I'm speaking mainly of their fans) are insufferable, but the Beavers are alright.
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From:edgyspice
Date:September 26th, 2008 09:53 pm (UTC)
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Bavarian pretzels w/sweet mustard, raclette cheese melted over potatoes, golden-fried weiner schnitzel, pork or veal bratwurst, cheese fondue, and a bouillon pot to cook beef, chicken, and sausage, served w/ 5 dipping sauces (garlic, horseradish cream, tartare, curry, and the cayenne-tinged "Santa Fe" -- viva Geneva?)

I feel full just reading that.
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From:rizwank
Date:September 27th, 2008 12:42 am (UTC)
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I realized I have spent too much time not writing *any* code at all, so sat down to write a quickie python script to prove that 43112609 is prime - in the least efficient way possible. [n = root(43112609). for i = 2 to n, do (43112609/i) and report back if the result is an int.

Then I realized that doing so was less interesting than contemplating how freaking big (2^43,112,609 - 1) is.
(no subject) - (Anonymous)
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From:rizwank
Date:September 27th, 2008 03:34 am (UTC)
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For finding whether a single number is prime or not?

Sieve : O((nlogn)(loglogn))

The divisor method should be much cheaper than that, it'll only do n^(1/2) divisions. [Of course, the proof lies in whether the division/int test is more expensive than the above multiplication, and, of course, it is. But by how much?]

Neat link though. Enjoyed reading it =)
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From:essentialsaltes
Date:September 27th, 2008 02:26 pm (UTC)
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Obviously you can partially incorporate the sieve by testing only the odd numbers from 3 to n. That'll save you half your time. And if you make use of known primes, you'll get even more efficient. Looks like you'll only have to test fewer than 1000 primes to get to n. But maybe using a list is cheating.
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From:richardabecker
Date:September 27th, 2008 05:47 am (UTC)
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Warsteiner Dunkel on tap. That would be something.

-- Richard
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From:colleency
Date:September 30th, 2008 06:45 am (UTC)
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Shawn and I were walking by Edelweiss tonight, and we saw friends sitting there, so we sat down to chat.

Our friend opted to eat outside, because it was too noisy inside. The airport noise was apparently quieter than the football game and children inside.

We weren't hungry, but we sampled our friends' dishes. One of our friends had the macaroni and cheese, which we dubbed macaroni and meat. It was cavatappi pasta with ground beef which had been cooked in a very small amount of tomato. The noodles weren't very cheesy. It was kind of like hamburger helper. Our other friend had mushroom and chicken in cream sauce over a potato pancake. It was very mild. Were I to order from their menu, I would try the raclette fondue with kirsch.

Our friend sampled two of the brews. He seemed to enjoy them. They served them in the correct glasses for the type of beer, too.
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From:essentialsaltes
Date:September 30th, 2008 01:57 pm (UTC)
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Thanks for the tip!
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From:castle_kevorah
Date:October 3rd, 2008 07:28 am (UTC)
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Maths hurtz mai rite-hemizfere-braned verbul/vizual long-winded writer brane. Duz not compoot. I is kneedin' a cheetsheet four pokur, I duz.

Edelweiss sounds fabulous, though. You & the Divine Miz Becca wanna maybe do a double datey type thing sometime Thanksgiving-sy or Decemberishly?

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From:essentialsaltes
Date:October 3rd, 2008 08:57 pm (UTC)
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A dinnery meeting sounds good to me.
But I think we'll pass on the LACMA ball Kev mentioned. Still not sure what, if anything, we're doing for Halloween.

Journal of No. 118