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-   -   is confusing (https://www.mersenneforum.org/showthread.php?t=19796)

zakary 2014-10-31 00:38

is confusing
 
my numbre with 101 019 520 digits. how can i display it in internet??

Batalov 2014-10-31 00:47

Just type it into a word document, zip it and post it.
Word documents zip much better than plain text files!

ixfd64 2014-10-31 00:48

Inb4miscmath.

Mini-Geek 2014-10-31 02:44

[QUOTE=zakary;386510]my numbre with 101 019 520 digits. how can i display it in internet??[/QUOTE]

Easy: just write [URL="http://www.mersenne.ca/exponent/335579581"]2^335,579,581-1[/URL]. At least, I'm guessing that's your "prime" number (plus or minus 2), since that's a Mersenne number with exactly that many digits (indeed, the only one with a prime exponent in a good range around that size). It's even without known factors (even after I pushed its TF 5 bits (and counting) higher than it was), so your crank score isn't quite as high as it could've been. Congrats on that!

Batalov 2014-10-31 03:21

Why not 2^(27!+1)-1 ? It is surely bigger and has no known factors... yet? Must be prime, too, and much bigger!

LaurV 2014-10-31 03:53

[QUOTE=Batalov;386518]Why not 2^(27!+1)-1 ? It is surely bigger and has no known factors... yet? Must be prime, too, and much bigger![/QUOTE]
because it has far more digits than claimed? :razz:

VBCurtis 2014-10-31 05:19

[QUOTE=LaurV;386520]because it has far more digits than claimed? :razz:[/QUOTE]

Batalov was asking the OP, not the guesser.

Primeinator 2014-10-31 06:02

[QUOTE=Batalov;386518]Why not 2^(27!+1)-1 ? It is surely bigger and has no known factors... yet? Must be prime, too, and much bigger![/QUOTE]

Out of curiosity ...

Digits in 2^p -1 are easy to calculate as ceiling_(p*log(2))

Is there a way to easily calculate the digits in something like x! ?

if P = 27! +1 it is clear that 2^p is much, much, much bigger than 100 M digits. I would like to be able to tell how many digits...

Batalov 2014-10-31 06:36

[CODE](23:33) gp > \p 30
realprecision = 38 significant digits (30 digits displayed)
(23:34) gp > (27!+1)*log(2)/log(10)
%4 = 3277876323445093851079375875.23[/CODE]=>
It has 3277876323445093851079375876 decimal digits, but it has the usual properties of Mersenne's. So the factors are of 2kp+1 form, and [TEX]\pm 1[/TEX] (mod 8). I haven't found a factor, but it doesn't mean someone couldn't find one. It could be fun! :smile:

P.S. And yes, I was suggesting a parallel to the OP's logic: "No factors are known, therefore it is surely a prime".

P.P.S. There is a Stirling formula for a pretty good estimate of the value of x!

LaurV 2014-10-31 06:40

3277876323445093851079375876 decimal digits.

(an idiot throws a stone in the lake and 100 sane scientists try to get it out... (romanian proverb))

[edit, grrr, I am always a step behind, hehe... ]
[edit 2: and yes, by idiot I was referring to OP, and not to Serge :razz:]
[edit 3: 2^M48-1 may be larger... or M48#+1 ? (we had this discussion at least ten times on this forum, now other people will jump in and say larger possible primes)]
[edit 4: scrap M48#, we can not construct it, as we don't know all primes up to it :wink:]

Uncwilly 2014-10-31 06:55

[QUOTE=Mini-Geek;386515]Easy: just write [URL="http://www.mersenne.ca/exponent/335579581"]2^335,579,581-1[/URL]. At least, I'm guessing that's your "prime" number (plus or minus 2), since that's a Mersenne number with exactly that many digits (indeed, the only one with a prime exponent in a good range around that size). It's even without known factors (even after I pushed its TF 5 bits (and counting) higher than it was), so your crank score isn't quite as high as it could've been. Congrats on that![/QUOTE]

If you haven't started a P-1 on it, I might be able to do that on one of my borg.


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