Se (3^n+1)-2=p, allora il prodotto 3^n*(3^n+1) è un numero perfetto dispari? Esempio: 3^3*3^4-2=27*79=2133- Divisori:1+3+9+27+79+237+711=1/2 ovvero...
24227
Maximilian Hasler
maximilian_h...
Apr 26, 2012 1:49 am
Ich nehme an, Sie wollten 3^(n+1)-2=p und 3^n*(3^(n+1)-2)=p schreiben, anstelle von (3^n+1)-2=p und 3^n*(3^n+1)-2=p ? Euklid's Theorem verbietet nicht, dass es...
24225
Maximilian Hasler
maximilian_h...
Apr 25, 2012 7:20 pm
see http://oeis.org/search?q=1%2C3%2C25%2C49%2C7381 and http://en.wikipedia.org/wiki/Wolstenholme%27s_theorem Maximilian ... [Non-text portions of this message...
24224
kadickv
Apr 25, 2012 5:20 pm
Please comment the following conjecture weather it's obvious or already known or new one Let 'N' be any odd number greater than 1 Calculate a/b =...
24223
paulunderwooduk
Apr 24, 2012 10:37 am
Hi, congrats to PrimeGrid for currently having about 50% of the top5000 world record primes: http://primes.utm.edu/bios/top20.php?type=project&by=PrimesRank ...
24222
Paul Leyland
paul@...
Apr 23, 2012 9:09 am
... Without any information on how you propose to find the t_i it's next to impossible to give any meaningful analysis of your algorithm. Paul...
24221
Kermit Rose
kermit1941
Apr 21, 2012 11:21 pm
Hello friends. I've constructed a factoring algorithm that I call ProportionateFactor because, to factor positive integer z, it seeks to find four integers ...
24220
Tom
tjw99
Apr 20, 2012 9:09 pm
North Carolina or Virginia....
24219
djbroadhurst
Apr 20, 2012 9:06 pm
... Definition: For positive integer n let p be the largest prime divisor of n*(n+1) and S(n) = log(n)/log(p) be the figure of merit for the smoothness of the ...
24218
Alan Eliasen
aeliasen
Apr 18, 2012 10:55 am
I posted this (shortened) to Twitter tonight: (I'm https://twitter.com/aeliasen ) I got this phone number from a girl named Jenny tonight. Her 7-digit number...
24217
Sebastian Martin Ruiz
s_m_ruiz
Apr 17, 2012 3:17 pm
Sorry. I promise not to send anything if I'm not sure that's interesting. ________________________________ De: Maximilian Hasler...
24216
Maximilian Hasler
maximilian_h...
Apr 16, 2012 9:51 pm
It's not nice to obfuscate simple expressions to make serious people loose their time. You should be banned from this group for writing things like ...
24215
Sebastian Martin Ruiz
s_m_ruiz
Apr 16, 2012 8:08 pm
Hello all: I have obtained a curious identity: Prime[(-1)^(PrimePi[n + 1 ] - PrimePi[n] + 1)*2(n + 1)*(PrimePi[n + 1 ] - PrimePi[n] - 1/2)] -...
24214
Robert Gerbicz
robertgerbicz
Apr 16, 2012 12:03 am
... Missed the condition that here the 4 terms should be positive, and in the Lagrange's theorem you can use 0 as a term. [Non-text portions of this message...
24213
WarrenS
warren_d_smi...
Apr 16, 2012 12:00 am
... --every positive integer is a sum of 4 squares (Fermat, Euler, Lagrange); the product of 4 squares is a square. QED. Note the word "composite" was not...
24212
Robert Gerbicz
robertgerbicz
Apr 15, 2012 3:56 pm
You can also generalize the problem for non-composites, the only exceptions are N=1,2,3,5, for the other cases these are good decompositions: ...
24211
Maximilian Hasler
maximilian_h...
Apr 15, 2012 2:15 pm
... N=ab=(p+q)(r+s)=pr+ps+qr+qs pr * ps * qr * qs = ( pqrs )^2 otherwise said, /any/ decomposition of the two factors of N into a sum leads to a decomposition...
24210
Kermit Rose
kermit1941
Apr 15, 2012 12:45 pm
Hello Friends. Prove that every positive composite integer can be expressed as a sum of 4 positive integers such that the product of the 4 positive integers is...
24209
paulunderwooduk
Apr 14, 2012 5:19 pm
... Combining fails with the composite counterexample n=256999 and x=32768, However, I have tested the 1+1+1+2 conjecture up to n<10^7, Paul -- restoring...
24208
paulunderwooduk
Apr 14, 2012 3:39 pm
... I ran some tests in the foothills and found refutations with the counterexamples: n=256999 x=32768 n=287051 x=10729 I can not see how to wriggle out of...
24207
Kermit Rose
kermit1941
Apr 13, 2012 1:50 pm
The following might or might not be progress in factoring theory. We seek the factors of z = r^4 + d3 r^3 + d2 r^2 + d1 r + d0, where d3,d2,d1,d0 are not...
24206
papadimitriou.vassilis
papadimitrio...
Apr 10, 2012 5:38 pm
According to Artin's conjecture, there is a positive constant A(a) such that asymptotically the proportion of primes p with morder(a,p) = p-1 among all primes...
Sorry someone has hacked my email. [Non-text portions of this message have been removed]...
24203
paulunderwooduk
Apr 1, 2012 9:02 pm
Hi, I have formulated another composite test variant: Non-square N>5, with gcd(30,N)==1, is prime if and only if for any integer x: gcd(x^3-x,N)==1 and ...
24202
bhelmes_1
Mar 27, 2012 8:00 pm
Hello Mark, i wrote a prime sieve with Cuda on a Gpu Geforce 450 with 192 cores. All work is done on the Gpu. I get as result only the numbers of primes in...
24201
Flavio Mattos
flavio_biker
Mar 27, 2012 10:42 am
Thanks for the nice words. Yes, Primo, plural Primos is the portuguese version of Prime. :-) This discussion was stimullating. I'll pursue betther performance...
24200
Jim White
mathimagics
Mar 27, 2012 7:24 am
I think Flavio's only to be encouraged in his learning process. Perhaps one useful lesson is this - as CPU speeds keep doubling the same can not be said...
24199
djbroadhurst
Mar 27, 2012 12:11 am
... They try to keep quiet about that episode, these days. However http://www.primegrid.com/forum_forum.php?id=19 still leaks some history on that "project" to...
24198
Mark Rodenkirch
mgrogue
Mar 26, 2012 10:47 pm
Since we're on the topic, has anyone tried to write a prime sieve that does most of the work in the GPU? -Mark...
