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Forum: Factoring 2013-03-21, 07:08
Replies: 148
Views: 21,832
Posted By m_f_h
Here I don't understand: Why a(42)? Only 16 terms...

Here I don't understand: Why a(42)? Only 16 terms are listed on OEIS. The next is is the least prime factor = 1 mod 4 of 1+4*product(a(1..16))^2. Do you have a(17)..a(41)?
Forum: Factoring 2013-03-21, 06:59
Replies: 148
Views: 21,832
Posted By m_f_h
I confirm the length, the two C472's are the...

I confirm the length, the two C472's are the product of earlier terms, +/- 1 (not sure whether this is a particular challenge and/or interesting for any reason beyond calculating some more terms)

...
Forum: Factoring 2013-03-21, 06:16
Replies: 148
Views: 21,832
Posted By m_f_h
Sean's list on the OEIS wiki

Following posts by Charles and Sean on the SeqFan list, I've created https://oeis.org/wiki/OEIS_sequences_needing_factors
I hope it might be useful to maintain Sean's list. (Maybe it could / should...
Forum: storflyt32 2013-03-21, 06:09
Replies: 16
Views: 1,386
Posted By m_f_h
I think anyone who comes to this forum with at...

I think anyone who comes to this forum with at least half-way serious intentions has already seen the well known factorization of 2^ab - 1 which is also valid for any other x^ab - 1 and based on the...
Forum: Math 2012-05-16, 23:24
Replies: 42
Poll: 9^(9^9)
Views: 4,020
Posted By m_f_h
Red face another 3 cents...

Well, in a case like this one, it is not *so* bad to write 9^(9^9) to make things 100% unambiguous. (Though I concede that a^b^c should mean a^(b^c), in particular because (a^b)^c could (and thus...
Forum: Puzzles 2009-10-23, 19:47
Replies: 35
Views: 2,135
Posted By m_f_h
3=3/1 is better : efficiency(3,1) = 2.82... ;-)

3=3/1 is better :
efficiency(3,1) = 2.82... ;-)
Forum: Lounge 2009-10-23, 18:09
Replies: 745
Views: 56,667
Posted By m_f_h
Compliance with Japanese GMP Standard

http://engrishfunny.com/2009/10/12/engrish-tightens-expert/
Forum: Puzzles 2009-10-19, 06:09
Replies: 10
Views: 612
Posted By m_f_h
how could he tell ?

how could he tell ?
Forum: Conjectures 'R Us 2009-10-19, 06:01
Replies: 880
Views: 75,753
Posted By m_f_h
Congrats on that nice prime. For k=404, I'd...

Congrats on that nice prime.

For k=404, I'd suggest to look for exponents = 8 (mod 12)...
Forum: Math 2009-10-01, 21:38
Replies: 17
Views: 1,880
Posted By m_f_h
How? (This is an incredulous "how" - Do...

How?

(This is an incredulous "how" -
Do you claim that this is possible?? (even, "theoretically" ?)
It is not, definitely! There are several irrefutable obstacles that make it provably...
Forum: Math 2009-10-01, 20:43
Replies: 13
Views: 1,275
Posted By m_f_h
To oversimplify a bit: I think he essentially...

To oversimplify a bit: I think he essentially wanted to know whether there are 2 different x such that x^2-2 = 0 (in Z/qZ).

Of course, if x is a solution, then -x is a solution too; e.g. 16 = -111...
Forum: Information & Answers 2009-10-01, 20:24
Replies: 14
Views: 936
Posted By m_f_h
Maybe the answer the O.P. was looking for is...

Maybe the answer the O.P. was looking for is rather something like

int factorial(int n){ int f=1; while( n>1 ) f *= n--; return(f); }

main(){ int n; for( n=1; n<10; n++ ) printf( "%d ! = %d\n",...
Forum: Lounge 2009-07-09, 02:09
Replies: 8
Views: 809
Posted By m_f_h
another broken link...

another broken link...
Forum: Puzzles 2009-04-11, 22:29
Replies: 33
Views: 1,823
Posted By m_f_h
Er... I really did think of tedrahedrons, but I...

Er... I really did think of tedrahedrons, but I don't know if I can pack what you say... should I ?
Specifically, I *was* thinking of a tedrahedron, but in my mind I had +1'd all dimensions, so...
Forum: Puzzles 2009-04-09, 22:51
Replies: 31
Views: 1,939
Posted By m_f_h
Continuation of the puzzle : prove or disprove...

Continuation of the puzzle : prove or disprove that A(n) >= 0 for all sufficiently large integers, where

A(n) = Smallest integer m, in absolute value, such that |m(n+m)| has as prime factors...
Forum: Puzzles 2009-04-09, 20:37
Replies: 31
Views: 1,939
Posted By m_f_h
Essentially your find() is the same as the highly...

Essentially your find() is the same as the highly unoptimized (in favour of utmost simplicity)

M(n)={ my(p=vector(primepi(sqrtint(n)),i,prime(i))~); for( m=1,1e9,
(factor(m*(n+m))[,1]==p |...
Forum: Puzzles 2009-04-08, 23:49
Replies: 33
Views: 1,823
Posted By m_f_h
The hint to consider the triangle as "black box"...

The hint to consider the triangle as "black box" with resistance proportional to side length.

Yes, or to 3 (or more?) dimensions. (triangle => tetrahedron)

PS: also agree with...
Forum: Miscellaneous Math 2009-04-05, 20:40
Replies: 62
Views: 2,603
Posted By m_f_h
Red face They should associate with Martin Musatov, who...

They should associate with Martin Musatov, who found several huge Mersenne primes, also solved the RH and some minor stuff (P=NP etc...):...
Forum: Puzzles 2009-03-29, 22:32
Replies: 43
Views: 2,369
Posted By m_f_h
If there may be some more spaces in the decoded...

If there may be some more spaces in the decoded message than in the crypted one, then
I think I figured it out...
Forum: Lounge 2009-03-28, 18:23
Replies: 4,137
Views: 264,175
Posted By m_f_h
[Calendar...

[Calendar (http://www.mersenneforum.org/calendar.php)] in the above navigation bar...???
Forum: Math 2009-02-22, 15:24
Replies: 26
Views: 1,334
Posted By m_f_h
That's a good point. Common speak would be in...

That's a good point. Common speak would be in favour of the latter (and btw not 0...999 but 1...1000, but since the 000 is unlikely to yield a prime, there's no problem) - and mathematically speaking...
Forum: Math 2009-02-22, 14:22
Replies: 26
Views: 1,334
Posted By m_f_h
Thumbs up You should submit this as "records in A038823...

You should submit this as "records in A038823 (http://www.research.att.com/%7Enjas/sequences/A038823)" with kw "fini".
Forum: Software 2009-02-22, 01:58
Replies: 5
Views: 1,234
Posted By m_f_h
There are different things. First, creating...

There are different things.

First, creating an array on runtime is not any different from "hard coding" it. And anyway, since you know the limits for a and x, you can create it once at the...
Forum: Homework Help 2009-02-01, 19:01
Replies: 50
Views: 5,136
Posted By m_f_h
Although this is not difficult to deduce(*), I...

Although this is not difficult to deduce(*), I agree that it is a less trivial property and makes 2.71828... indeed a little more "special".

--

(*) If I made no error in stupidly calculating...
Forum: Lounge 2009-02-01, 14:13
Replies: 4,137
Views: 264,175
Posted By m_f_h
http://reprap.org/ - a potentially...

http://reprap.org/ - a potentially self-reproducing 3D printer
Showing results 1 to 25 of 432

 
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