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42nd Mersenne Prime Confirmed
Jazzer_Techie writes "The possible Mersenne Prime discovered last week has now been confirmed. This prime has 7,816,230 digits, which makes it not only the largest Mersenne Prime, but also the largest prime of any kind ever discovered. For those who don't want to take time to read the article, the prime is 2^25,964,951 - 1."
2^25,964,951-1th post!!
Ha, eat that first post guy!
A morning without coffee is like something without something else.
There actually are very good algorithms for finding primality. It has reached the point where proving a number prime is MUCH easier than finding any factors of it.
There are two types. One is deterministic, and will give you absolute proof that the tested number is prime. The other type is probability based. These are more popular. The most widely used is known as the Miller-Rabin test. It is known to be absolutely correct for all n 3*10^16. For larger n, it will never report a composite to be prime, but there is a small (around 10^-20) chance the "prime" number will be composite. There are no known prime numbers that Miller-Rabin reports to be composite.
In the case of Mersenne numbers, it's a different story. There is a deterministic algorithm called the Lucas-Lehmer test. This will determine whether 2^p-1 is prime with O-notation p! The catch of course is that it only works for Mersenne numbers.
E = m c^3 Don't drink and derive E = m c^3
that the digits make a phone number?? 225-964-9511 used to dial the residence of a man in Baton Rouge, Louisiana.
Now all you get is "the number you have dialed is not a working number"
Could this be the first telephone slashdotting in history!?
Sounds a bit like my little (pretty useless) text compression test, I did a batch script that copied a file into another 1024 times (where the first file was a plain-text file with just a "b"), then I did the same with the new file, and then the same thing again, in the end getting a single 1 GiB file filled with the same character over and over again (bbbbb...).
Now that's all nice and such, but there's one more step to go, compressing that 1 GiB file... to one rar archive, with a grand size of 65,7 KiB (67 294 bytes)
Not necessarily: suppose p1=2, p2=3, p3=5, p4=7, p5=11, p6=13. Then p1*p2*p3*p4*p5*p6 + 1 = 30031 = 59 * 509
While p_1*...*p_n + 1 isn't divisible by any of the p_i, it might be divisible by some other prime.
Wikileaks, no DNS