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2011-01-26, 21:14   #23
axn

Jun 2003

124016 Posts

Quote:
 Originally Posted by davar55 Could someone solve for a,b,c,d,e,v,w,x,y,z ?
http://www.factordb.com/index.php?query=2^2011-1

Last fiddled with by axn on 2011-01-26 at 21:14

2011-01-27, 10:03   #24
Merfighters

Mar 2010
On front of my laptop

11101112 Posts

Quote:
 Originally Posted by davar55 So the factors are p7 * p42 = 54491.....71953 * c558 = abcde.....vwxyz. Could someone solve for a,b,c,d,e,v,w,x,y,z ?
This one?
(a,b,c,d,e,v,w,x,y,z)=(1,9,8,6,7,8,7,4,7,9)

 2011-01-28, 16:52 #25 cmd     "(^r'°:.:)^n;e'e" Nov 2008 ;t:.:;^ 17478 Posts p7 = 2171881 _42+ 558= ____ 6oo ckd === @ew .. we now return to good and stop ... he||o .
2011-01-29, 10:56   #26
xilman
Bamboozled!

May 2003
Down not across

2·5,101 Posts

Quote:
 Originally Posted by davar55 Ah but my MPA calculator doesn't factor that high, so I'd have to let it divide by the p7 and p42 first, which I'd have to key in. And my electronic pocket calculators are FP-Scientific, so I only get 1 bit of precision ( ).

In the late 70's, long before I had access to computers, I was doing these sorts of computations with a simple floating point calculator.

Paul

2011-01-31, 18:22   #27
ewmayer
2ω=0

Sep 2002
República de California

7×23×71 Posts

Quote:
 Originally Posted by xilman Think about modular arithmetic. In the late 70's, long before I had access to computers, I was doing these sorts of computations with a simple floating point calculator.
Yes, but were you using balanced-digit transform-based modmuls?

2011-01-31, 21:09   #28
xilman
Bamboozled!

May 2003
Down not across

2·5,101 Posts

Quote:
 Originally Posted by ewmayer Yes, but were you using balanced-digit transform-based modmuls?
No, but for evaluating the leading five and trailing five digits of a simple multiplication, division, remainder or exponentiation I didn't need to.

We had it tough. There was a time when I could do it on a slide rule though I then had to work in radix 1000 and take care to check the final digit with mental calculation.

Try telling the youth of today that, and they won't believe you.

Paul

 2011-02-19, 22:44 #29 Flatlander I quite division it     "Chris" Feb 2005 England 31·67 Posts Some soccer thingy by the local lads. Crawley 0 - 1 Man Utd Crawley did better than I thought they would, I guessed 1 - 5. Though Man Utd weren't on top form apparently. An anagram: Crawley rules ok. = Or we really suck.
 2011-04-22, 19:11 #30 davar55     May 2004 New York City 22×7×151 Posts Thanks for those factoring programs and dbs. Collecting here a bit: 2^2011-1 = 2171881, 544919289684132720332849364364039531371953, * If I counted digits on my fingers correctly, then: 2^2011-1 = p7 * p42 * c558 So it factors as: p7 * p42 = 54491.....71953 * c558 = 19867.....87479 I'll have to see how 2^2012-1 factors. I doubt the world will end before I do.
 2014-12-14, 04:07 #31 davar55     May 2004 New York City 108416 Posts With my multi-precision integer calculator: 2^2012-1 = C606 = 47027.....24095 = 3 * 5 * 6037 * 10061 * C597 C597 = 51617.....76289 From factordb, it is already completely factored.