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Messages 8977 - 9007 of 9803   Oldest  |  < Older  |  Newer >  |  Newest
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8977
Hi, I have determined, heuristically, that the sum of primes < n ~ n^2/(2*log(n)-1). I did this by doing the "Noble" thing and supporting evidence of sums of...
cino hilliard
hillcino368
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Jun 4, 2008
9:04 pm
8978
Hey Cino, Sorry for the layman comments, as probably no one will react onto your posting. Thanks for doing the great job of trying to find a connection/link ...
Vincent Diepeveen
diepchess
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Jun 4, 2008
9:55 pm
8979
see also: %F A007504 a(n) has the asymptotic expression a(n) ~ n^2 * log(n) / 2. - Ahmed Fares, Apr 24 2001 on OEIS, and...
mad_math_max
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Jun 5, 2008
11:58 am
8980
... I like how the cranks will just high-five each other, rather than doing a simple Google search, which would have revealed that someone has already studied...
Décio Luiz Gazzoni...
deciogazzoni
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Jun 5, 2008
11:58 am
8982
Here it is again. Sorry for the jumble in the last post. Drat hotmail to yahoo conversion. I deleted the bad one and did this one in the yahoo primeform group....
Cino Hilliard
hillcino368
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Jun 6, 2008
6:28 pm
8983
to me anyway... let x = ((3+sqrt(5))/2); let n be some odd number; iff (x^n (rounded up)) mod n == 3 and (x^((n+1)/2) (also rounded up)) mod 2 == 1, (odd...
leavemsg1
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Jun 8, 2008
12:47 am
8984
... forprime(p=1,199,ceil(((sqrt(5)+3)/2)^((p+1)/2))%2 | print1(p",")) 5,11,17,23,29,41,47,53,59,71,83,89,101,107,113,131,137,149,167,173,179,191,197, there...
mad_math_max
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Jun 8, 2008
5:26 am
8985
... As a side note: This is known since several thousand years....
mad_math_max
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Jun 8, 2008
5:26 am
8986
... Indeed. Here's a much better formula: est6(n)=n^2/2/(log(n)-c-d/log(n)-e/log(n)^2) with c=1/2,d=1/4,e=2/5 gives: est6(10^10)/2220815456739024823-1. =...
mad_math_max
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Jun 8, 2008
5:26 am
8987
Hi Max, Glad you enjoyed tweeking my beautiful formula est5 =n^2/(2*log(n)-1). Take it easy. Just kidding. Seriously, though, I will use your formula when new...
cino hilliard
hillcino368
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Jun 8, 2008
11:04 am
8988
... er... not sure the 5 should be squared... ... I think I tried to do a copy-paste from your post... ... ah, nostalgy... but.... wasn't it rather 48 K of...
mad_math_max
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Jun 8, 2008
2:16 pm
8989
from&nbsp; W.E.&nbsp;&nbsp; i just wanted to say that using x for a const is not a good idea.&nbsp; But more impt i have given this constant the...
W. E.
we_6107_31
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Jun 8, 2008
7:34 pm
8990
To: primeform@yahoogroups.com From: oeis-2008@... Date: Sun, 8 Jun 2008 14:07:37 +0000 Subject: [primeform] Re: (sum of primes < n) Serendipity strikes...
cino hilliard
hillcino368
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Jun 9, 2008
12:51 am
8991
... sorry,... it should be... this statement [(x^((n+1)/2) (also rounded up)) mod n] mod 2 == 1, (odd result), now it's right... proofreading... I hate it....
leavemsg1
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Jun 9, 2008
12:52 pm
8992
it does, if I were to proofread my e-mail... look at the last post... now it's valid. ... From: W. E. &lt;renga_ya@...&gt; Subject: Re: [primeform]...
Bill Bouris
leavemsg1
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Jun 9, 2008
3:34 pm
8993
look at my last corrected post... now it should get them all if&nbsp;you calculate it correctly ... From: mad_math_max &lt;oeis-2008@...&gt; Subject:...
Bill Bouris
leavemsg1
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Jun 9, 2008
3:35 pm
8994
... ********************************** I think the proof may be as follow Let P prime = 2*n+1 , n=(P-1)/2 The sum of odd numbers from 1 to P is (n+1)^2 or...
Pierre CAMI
pierrecami
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Jun 10, 2008
2:46 pm
8995
Hi, ... prime ... (log ... Yep, this is pretty much the way I did it in http://tech.groups.yahoo.com/group/primeform/message/8982 In a later post, I...
Cino Hilliard
hillcino368
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Jun 10, 2008
7:34 pm
8996
... This is a weak pseudoprimality test, which fails for 158 composite odd integers n with 3 < n < 10^6: ...
David Broadhurst
djbroadhurst
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Jun 11, 2008
2:03 am
8997
You wrote: Re: interesting primality test: "it's from an article on T3 sequences (primality test)". Could you point me to the article, or email me a copy? I'm...
Paul_M_Bay
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Jun 13, 2008
11:01 pm
8998
Re: interesting primality test, Based on the listing below, the 2nd part of the test appears to have a consistency: Excluding the primes n=2 which is even, and...
Paul_M_Bay
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Jun 13, 2008
11:01 pm
8999
Here's a computational look at a T3 sequence. &nbsp; say you choose 17 then calc. terms Tn T0 = 2, T1 = 3, T2 = 7 or&nbsp;T2 = T1^2-2 = 3^2-2 = 7 mod 17 = 7, ...
Bill Bouris
leavemsg1
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Jun 15, 2008
11:43 pm
9000
... which is a weak Lucas test. The recursion T(n)= if(n==0,2,if(n==1,3,if(n%2,T((n-1)/2)*T((n+1)/2)-3,T(n/2)^2-2))) is solved by the Lucas sequence ...
David Broadhurst
djbroadhurst
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Jun 16, 2008
8:26 am
9001
... PS: Here are some strong pseudoprimes that pass the Lucas test with kronecker(5,n)=-1 {strong(n)=kronecker(5,n)==-1&& ...
David Broadhurst
djbroadhurst
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Jun 16, 2008
9:09 am
9002
it fails with 9, even,&nbsp;and 15, etc. but this can be&nbsp;ruled out if the last step before. let's say T9 for the case of T17 were EVEN 15 does fail the...
Bill Bouris
leavemsg1
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Jun 16, 2008
4:16 pm
9003
sorry for getting uptight w/you Mr. Broadhurst. here's my final attempt to explain away the skepticism. take a number, say 23; compute all the following terms...
leavemsg1
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Jun 16, 2008
6:33 pm
9004
... This test will not detect that n = 323 is composite. Your sequence is http://www.research.att.com/~njas/sequences/A005248 Hence the test T(k) =...
David Broadhurst
djbroadhurst
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Jun 17, 2008
3:22 am
9005
... Try it with n=377, where T((n+1)/2)%n is odd. ... Here is a relevant benchmark: On an 2.2 GHz Opteron machine, the BPSW pseudoprimality test of Pari-GP...
David Broadhurst
djbroadhurst
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Jun 19, 2008
7:45 am
9006
It's easy to construct a titanic Bouris-pseudoprime: c1029 = (10*137^240 + 897457)*(60*137^240 + 5384749); ...
David Broadhurst
djbroadhurst
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Jun 19, 2008
11:25 am
9007
Mr. Chickhurst... j/k wow,... you use a lot of jargon that I'm familiar with, but is it really necessary ??? I noticed that 9 and 15 won't pass the T3 sequence...
leavemsg1
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Jun 19, 2008
1:47 pm
Messages 8977 - 9007 of 9803   Oldest  |  < Older  |  Newer >  |  Newest
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