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50th Mersenne Prime found!
Posted: Tue Jan 09, 2018 10:42 pm
by neufer
https://en.wikipedia.org/wiki/Largest_known_prime_number wrote:
<<As of January 2018, the largest known prime number is 2
77,232,917 − 1, a number with 23,249,425 digits. It was found in December 2017 by the Great Internet Mersenne Prime Search (GIMPS). A standard word processor layout (50 lines per page, 75 digits per line) would require 6,199 pages to display it. Its value is:
467333183359231099988335585561115521251321102817714495798582338593567923480521177207484311099740208849621368090038049317... (23,249,185 digits omitted)
...285376004518786055402223376672925679282131965467343395945397370476369279894627999939614659217371136582730618069762179071 >>
Re: 50th Mersenne Prime found!
Posted: Wed Jan 10, 2018 4:21 am
by BDanielMayfield
Base 10 is just too insufficient for such enormous numbers. I looked into higher bases once when Art had made a similar post, but wasn't able to find anything higher than hexadecimal (base 16) in common use. What's called for is a much higher base system, say, base 100, in which there would be 100 characters to represent the base ten numbers 0 to 99. Such a system would be able to compress the exact expression of a humongously long real number into a more manageable size.
Have any large base systems been developed?
Bruce
Re: 50th Mersenne Prime found!
Posted: Wed Jan 10, 2018 4:50 am
by Chris Peterson
BDanielMayfield wrote:What's called for is a much higher base system, say, base 100, in which there would be 100 characters to represent the base ten numbers 0 to 99. Such a system would be able to compress the exact expression of a humongously long real number into a more manageable size.
It would allow the number to be printed using less paper. I don't see what other value it would have. Would you or I have a better grasp of the number if it were notated in base 100?
No, going the other way is what makes the most sense. Expressing it in binary. Because once a number becomes to large to make any intuitive sense expressed in base 10, it's probably only being manipulated in a computer, anyway, and for that, base 2 is the natural system.
(The ancient Babylonians utilized base 60, sexagesimal. AFAIK that's the largest base ever used for common math.)
Re: 50th Mersenne Prime found!
Posted: Wed Jan 10, 2018 6:04 am
by BDanielMayfield
Chris Peterson wrote:BDanielMayfield wrote:What's called for is a much higher base system, say, base 100, in which there would be 100 characters to represent the base ten numbers 0 to 99. Such a system would be able to compress the exact expression of a humongously long real number into a more manageable size.
It would allow the number to be printed using less paper. I don't see what other value it would have. Would you or I have a better grasp of the number if it were notated in base 100?
Being able to accurately express something in a much more efficient manner has value. Using less paper is good.
No, going the other way is what makes the most sense. Expressing it in binary. Because once a number becomes to large to make any intuitive sense expressed in base 10, it's probably only being manipulated in a computer, anyway, and for that, base 2 is the natural system.
15
(base 10) = F
(base 16) = 1111
(base 2), therefore hex is more efficient than the decimal and especially the binary systems, at least in character count. The 50th Mersenne Prime would require a staggering number of digits in binary.
(The ancient Babylonians utilized base 60, sexagesimal. AFAIK that's the largest base ever used for common math.)
Very good to know. Thanks.
Bruce
Re: 50th Mersenne Prime found!
Posted: Wed Jan 10, 2018 2:48 pm
by rstevenson
15(base 10) = F(base 60) too.
There are lots of base conversion tools available online -- if you
really have nothing else to do.
Rob
Re: 50th Mersenne Prime found!
Posted: Wed Jan 10, 2018 2:49 pm
by Chris Peterson
BDanielMayfield wrote:15(base 10) = F(base 16) = 1111(base 2), therefore hex is more efficient than the decimal and especially the binary systems, at least in character count. The 50th Mersenne Prime would require a staggering number of digits in binary.
And yet, that's precisely how it was found. Binary computation. Internal binary representation. (Computers don't use hexadecimal.)
Re: 50th Mersenne Prime found!
Posted: Wed Jan 10, 2018 3:26 pm
by neufer
BDanielMayfield wrote:
The 50th Mersenne Prime would require a staggering number of digits in binary.
- 77,232,917 bits to be precise:
111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111... (77,232,677 bits omitted)
...111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111
but, at least, it would be easy to remember (so long as you were allowed to count on your fingers).
Re: 50th Mersenne Prime found!
Posted: Wed Jan 10, 2018 3:31 pm
by Chris Peterson
neufer wrote:BDanielMayfield wrote:
The 50th Mersenne Prime would require a staggering number of digits in binary.
- 77,232,917 bits to be precise:
Bit. As in
binary dig
it.
51th Mersenne Prime found!
Posted: Fri Jul 31, 2020 6:26 pm
by neufer
https://en.wikipedia.org/wiki/Largest_known_prime_number wrote:
<<The largest known prime number (as of January 2020) is 2
82,589,933 − 1, a number which has 24,862,048 digits when written in base 10. It was found via a computer volunteered by Patrick Laroche of the Great Internet Mersenne Prime Search (GIMPS) in 2018. Its value is:
148894445742041325547806458472397916603026273992795324185271289425213239361064475310309971132180337174752834401423587560... (24,861,808 digits omitted)
...062107557947958297531595208807192693676521782184472526640076912114355308311969487633766457823695074037951210325217902591.>>
Re: 51th Mersenne Prime found!
Posted: Fri Jul 31, 2020 7:42 pm
by Ann
neufer wrote: ↑Fri Jul 31, 2020 6:26 pm
https://en.wikipedia.org/wiki/Largest_known_prime_number wrote:
<<The largest known prime number (as of January 2020) is 2
82,589,933 − 1, a number which has 24,862,048 digits when written in base 10. It was found via a computer volunteered by Patrick Laroche of the Great Internet Mersenne Prime Search (GIMPS) in 2018. Its value is:
148894445742041325547806458472397916603026273992795324185271289425213239361064475310309971132180337174752834401423587560... (24,861,808 digits omitted)
...062107557947958297531595208807192693676521782184472526640076912114355308311969487633766457823695074037951210325217902591.>>
That's a funny shape of that curve. Reminds me somehow of the Universe with expands faster or slower during different epochs.
Although, unlike the Universe, the prime number curve seems to be slowing down.
Ann
Re: 51th Mersenne Prime found!
Posted: Fri Jul 31, 2020 7:54 pm
by Chris Peterson
Ann wrote: ↑Fri Jul 31, 2020 7:42 pm
neufer wrote: ↑Fri Jul 31, 2020 6:26 pm
https://en.wikipedia.org/wiki/Largest_known_prime_number wrote:
<<The largest known prime number (as of January 2020) is 2
82,589,933 − 1, a number which has 24,862,048 digits when written in base 10. It was found via a computer volunteered by Patrick Laroche of the Great Internet Mersenne Prime Search (GIMPS) in 2018. Its value is:
148894445742041325547806458472397916603026273992795324185271289425213239361064475310309971132180337174752834401423587560... (24,861,808 digits omitted)
...062107557947958297531595208807192693676521782184472526640076912114355308311969487633766457823695074037951210325217902591.>>
That's a funny shape of that curve. Reminds me somehow of the Universe with expands faster or slower during different epochs.
Although, unlike the Universe, the prime number curve seems to be slowing down.
Ann
Careful... the y-axis is logarithmic. The declining slope of the curve only indicates "slowing down" in certain contexts.
Flattening the Curve
Posted: Sat Aug 01, 2020 12:24 am
by BDanielMayfield
Chris Peterson wrote: ↑Fri Jul 31, 2020 7:54 pm
Ann wrote: ↑Fri Jul 31, 2020 7:42 pm
That's a funny shape of that curve. Reminds me somehow of the Universe with expands faster or slower during different epochs.
Although, unlike the Universe, the prime number curve seems to be slowing down.
Ann
Careful... the y-axis is logarithmic. The declining slope of the curve only indicates "slowing down" in certain contexts.
Right Chris. It would become a favorite tool of flat Earth type thinkers, if they could grasp the concept. Most any curve can be flattened simply by switching to a log or semi-log graph.
Re: 51th Mersenne Prime found!
Posted: Sat Aug 01, 2020 2:17 am
by neufer
Ann wrote: ↑Fri Jul 31, 2020 7:42 pm
That's a funny shape of that curve. Reminds me somehow of the Universe with expands faster or slower during different epochs. Although, unlike the Universe, the prime number curve seems to be slowing down.
The Universe had 2 kicks in the butt after the Big Bang:
Mersenne prime discovery has had 3 kicks in the butt in the last hundred years:
- Electronic computers ~1960
Massively parallel computers ~1985
Large scale distributed computing projects ~2000
It is unclear where the next kick in the butt will come from.
Quantum computing 
Perhaps (some subset of) the
Mersenne prime exponents have some (as yet) undetermined regularity:
2, 3, 5, 7, 13, 17, 19, 31, 61, 89, 107, 127, 521, 607, 1279, 2203, 2281, 3217, 4253, 4423, 9689, 9941, 11213, 19937, 21701, 23209, 44497, 86243, 110503, 132049, 216091, 756839, 859433, 1257787, 1398269, 2976221, 3021377, 6972593, 13466917, 20996011, 24036583, 25964951, 30402457, 32582657, 37156667, 42643801, 43112609, 57885161, 74207281, 77232917, 82589933, ...
(Blue color: proven consecutive Mersenne prime exponents.)
