PlanetMath (more info)
 Math for the people, by the people. Sponsor PlanetMath
Encyclopedia | Requests | Forums | Docs | Wiki | Random | RSS  
Login
create new user
name:
pass:
forget your password?
Main Menu
[parent] Viewing Message
``Re: related problem'' by eddik on 2006-08-27 11:51:48
Thank You for your fast reply!
>>Thus A may be any integer between b/r-c/|r| and b/r+c/|r|

In the problem i meant the integer b is not fixed but depends on the choice of A (resp. a in my first post). That is, given real r and c>0, we are looking for all positive integers A for which A*r is not too far away from the nearest integer.

I did some experiments yesterday using Mupad. The result: the A's seem to have a regular behavior relative to their succesive differences. For example if we look at the first 500000 multiples of r=0.2703567032 (1*r,...,500000*r), so we get 10016 possible values for A with A*r at most 1/100 away from the nearest integer. I've numbered these A's and considered the succesive differences A_(i+1)-A_(i) and discovered that each of them takes one of the tree
possible values 122, 85 and 37 (notice that 122=85+37; this was true in all my considered examples except of them where fewer than 3 values were taken; there were never more than 3 possible values for the succesive differences, but it may be when we consider more then 500000 multiples). With the above r and c I get the first 100 succesive differences as below:
 [37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37,
 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37,
 122, 37, 37, 37, 37, 37, 37, 85, 37, 37, 37, 37, 37, 37, 122, 37,
 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37,
 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37, 37,
 37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 122,
 37, 37, 37, 37]
while the 101 in the middle are
 [37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37,
 122, 37, 37, 37, 37, 37, 37, 85, 37, 37, 37, 37, 37, 37, 122, 37,
 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37,
 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 37, 85, 37, 37,
 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37,
 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37, 37,
 37, 37, 122, 37, 37]
and number 915-1015:
[37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 37,
 85, 37, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37,
 37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 122,
 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 37, 122, 37, 37, 37,
 37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37,
 37, 37, 37, 37, 122, 37, 37, 37, 37, 37, 122, 37, 37, 37, 37, 37,
 37, 85, 37, 37, 37].
The same setting with r:=0.8142678572 yields 1000 desirable A's among the first 500000 integers with the successive differences as follows:
Number 1-100:
 [70, 70, 43, 27, 43, 27, 43, 27, 43, 27, 43, 27, 43, 70, 70, 70, 70,
 70, 70, 43, 27, 43, 27, 43, 27, 43, 27, 43, 70, 70, 70, 70, 70, 70,
 70, 43, 27, 43, 27, 43, 27, 43, 27, 43, 70, 70, 70, 70, 70, 70, 70,
 43, 27, 43, 27, 43, 27, 43, 27, 43, 70, 70, 70, 70, 70, 70, 70, 43,
 27, 43, 27, 43, 27, 43, 27, 43, 70, 70, 70, 70, 70, 70, 43, 27, 43,
 27, 43, 27, 43, 27, 43, 27, 43, 70, 70, 70, 70, 70, 70, 43]
Number 450-550:
 [43, 27, 43, 27, 43, 27, 43, 70, 70, 70, 70, 70, 70, 70, 43, 27, 43,
 27, 43, 27, 43, 27, 43, 70, 70, 70, 70, 70, 70, 70, 43, 27, 43, 27,
 43, 27, 43, 27, 43, 70, 70, 70, 70, 70, 70, 43, 27, 43, 27, 43, 27,
 43, 27, 43, 27, 43, 70, 70, 70, 70, 70, 70, 43, 27, 43, 27, 43, 27,
 43, 27, 43, 70, 70, 70, 70, 70, 70, 70, 43, 27, 43, 27, 43, 27, 43,
 27, 43, 70, 70, 70, 70, 70, 70, 70, 43, 27, 43, 27, 43, 27, 43]
and number 899-999:
[27, 43, 70, 70, 70, 70, 70, 70, 43, 27, 43, 27, 43, 27, 43, 27, 43,
 27, 43, 70, 70, 70, 70, 70, 70, 43, 27, 43, 27, 43, 27, 43, 27, 43,
 70, 70, 70, 70, 70, 70, 70, 43, 27, 43, 27, 43, 27, 43, 27, 43, 70,
 70, 70, 70, 70, 70, 70, 43, 27, 43, 27, 43, 27, 43, 27, 43, 70, 70,
 70, 70, 70, 70, 70, 43, 27, 43, 27, 43, 27, 43, 27, 43, 70, 70, 70,
 70, 70, 70, 43, 27, 43, 27, 43, 27, 43, 27, 43, 27, 43, 70, 70].

Is there anything known about these A's in the literature? Is there a formula describing it? Any ideas?

Greetings,
eddik

 
[ reply | up | top ]
Interact
reply