## 100000 pupils verify 2^9689-1

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• 2^9689-1 is prime! This was first proved by computer in 1963. There has been controvercy since the 4 color theorem was allegedly proved with use of a
Message 1 of 4 , Apr 1, 2004
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2^9689-1 is prime!

This was first "proved" by computer in 1963. There has been controvercy since
the 4 color theorem was allegedly proved with use of a computer. Many
mathematicians still refuse to accept computer proofs. To their satisfaction,
2^9689-1 is now the largest prime which has been verified manually. It has not
been verified whether it is the 21st Mersenne prime.

The computation was performed by 100000 pupils in Danish schools and completed
today.
The project was proposed and organized by math students. The purpose was to make
pupils train pen-and-paper calculations, plus make them interested in
collaboration and mathematics.
Computers (yes, the darn things) were originally used to split the Lucas-Lehmer
test using DWT FFT into millions of subtasks which could then be verified in
parallel. Every subtask was performed by two independent pupils not knowing the
computer result. When results did not match, a third computation was performed.
High school and math students verified manually that all the subtasks really did
amount to a primality proof.
The 1/4 million sheets of handwritten calculations will be used to form
"2^9689-1" on a 1/4 km^2 field photographed from space.

--
Jens Kruse Andersen
• ... ... I d rather trust a computer instead of 100,000 students doing it manually... Quite a feat though.
Message 2 of 4 , Apr 1, 2004
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At 05:16 AM 4/1/2004, Jens Kruse Andersen wrote:
>2^9689-1 is prime!
>
>This was first "proved" by computer in 1963. There has been controvercy since
>the 4 color theorem was allegedly proved with use of a computer. Many
>mathematicians still refuse to accept computer proofs.

...

I'd rather trust a computer instead of 100,000 students doing it
manually... Quite a feat though.
• Thursday, April 01, 2004 12:16 PM [GMT+1=CET], ... Do danish turn fool today? Best regards, Ignacio Larrosa Cañestro A Coruña (España) ilarrosa@mundo-r.com
Message 3 of 4 , Apr 1, 2004
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Thursday, April 01, 2004 12:16 PM [GMT+1=CET],
Jens Kruse Andersen <jens.k.a@...> escribió:

> 2^9689-1 is prime!
>
> This was first "proved" by computer in 1963. There has been
> controvercy since the 4 color theorem was allegedly proved with use
> of a computer. Many mathematicians still refuse to accept computer
> proofs. To their satisfaction, 2^9689-1 is now the largest prime
> which has been verified manually. It has not been verified whether it
> is the 21st Mersenne prime.
>
> The computation was performed by 100000 pupils in Danish schools and
> completed today.
> ...

Do danish turn fool today?

Best regards,

Ignacio Larrosa Cañestro
A Coruña (España)
ilarrosa@...
• ... And who should rather be trusted on April 1? ;-) Has anybody made a program which deliberately gave a bogus result on April 1? A mean example would be
Message 4 of 4 , Apr 1, 2004
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Jud McCranie wrote:
> At 05:16 AM 4/1/2004, Jens Kruse Andersen wrote:
> >2^9689-1 is prime!
> >
> >This was first "proved" by computer in 1963. There has been controvercy since
> >the 4 color theorem was allegedly proved with use of a computer. Many
> >mathematicians still refuse to accept computer proofs.
>
> ...
>
> I'd rather trust a computer instead of 100,000 students doing it
> manually... Quite a feat though.

And who should rather be trusted on April 1? ;-)

Has anybody made a program which deliberately gave a bogus result on April 1?
A mean example would be GIMPS' prime95 report a prime on tests completing that
day.

--
Jens Kruse Andersen
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