| View previous topic :: View next topic |
| Author |
Message |
k1ll3rdr4g0n
-
Joined: 04 Jul 2004
Posts: 609
|
 Posted: Sun Dec 05, 2004 4:00 pm Post subject: Facotring a large number |
 |
|
How would i go about facotrings a large number like:
31074182404900437213507500358885679300373460228427
27545720161948823206440518081504556346829671723286
78243791627283803341547107310850191954852900733772
4822783525742386454014691736602477652346609
i dont need someone to tell me the acctual factors just a jump start. Because i thought it was divisible by 3, it wasnt i thought it was divisible by 7, and it wasnt. I would want to almost say its divible by 9, but 9 isnt prime.
anyone help please? :(
_________________
 |
|
| Back to top |
   |
 |
needforspeed
-
Joined: 20 Oct 2003
Posts: 69
Location: Kansas
|
| Posted: Sun Dec 26, 2004 6:26 pm Post subject: |
|
|
do you want to find the Prime factorization?
Here's psuedocode for a simple algorithm to compute the prime factorization of a number:
| Code: |
Algorithm:
i = 2;
starting at i, find smallest prime p ≤ n ∋ pn, do
if found
then // n = pq, q is the quotient
n = q;
i = p
output p;
endif;
|
Here's psuedocode for The Sieve of Eratosthenes, a better algorithm.
| Code: |
construct a table of integers from 2 to n;
i = 2;
while i ≤ √n
remove all multiples of i, except i, from the table;
starting from i, scan the table to find
the first integer j remaining;
if found
then i = j
else stop (and return)
endif
endwhile;
|
I copied these algorithms directly from my notes from a few semesters ago.
_________________
My site and forums |
|
| Back to top |
  |
|
k1ll3rdr4g0n
-
Joined: 04 Jul 2004
Posts: 609
|
| Posted: Tue Dec 28, 2004 10:07 pm Post subject: |
|
|
Thank you but your a little late I found the The Sieve of Eratosthenes at mathworld.wolfram.com/SieveofEratosthenes.html and Ive been working on it ever since :). You can view pic of my progress here http://www.theunderground.ath.cx/images/prime_project/ . Wanna help me work on this xD?
_________________
|
|
| Back to top |
|
|
needforspeed
-
Joined: 20 Oct 2003
Posts: 69
Location: Kansas
|
| Posted: Thu Jan 06, 2005 12:44 am Post subject: |
|
|
what exactly are you trying to do anyway?
_________________
My site and forums |
|
| Back to top |
|
|
|
