
Introduction
----------------

With this  program you can:



Obtain a Vector indicating for any N < 2147483000  how many numbers 
there are with 2,3,4,5,6 ....divisors.For instance for
N = 50  the Vector is:
1,1/ 2,15/ 3,4/ 4,15/ 5,1/ 6,8/ 7,0/ 8,4/ 9,1/ 10,1.That means
 that up to 50 there are 15 prime numbers,4 numbers with 3 divisors,
 15 numbers with 4 divisors ,one number with 5 divisors,
 8 numbers with 6 divisors ,no number with 7 divisors ,
 4 numbers with 8 divisors,1 number wirh 9 divisors and 
 1 number with 10 divisors.

Obtain lists of numbers characterized by the same number of their 
divisors.For instance the first 2000 numbers with 100 divisors.
N>3,N<2147483000





If you write datas into files when asked by rhe program, it will 
be possible to draw curves and graphs and make other kind of 
calculation with other applications.Furthermore any screen can be copied 
to the bloc  note or printed by pressing the key "Stamp".
Change the properties of the windows for one option or the other.


Installation.
-------------

 The zip file contains the following files:
diviso10.exe
arr2.dat
vett1.dat
vett2.dat
readme.txt  (this file)

Extract them to a directory for example C:\divisors

Run diviso10.exe


Example
---------- 
Alt+enter to obtain full screen

Option 1.

 Enter  1000000000 and after about 40 secs you get the indication
  V E C T O R  R E A D Y
.Press enter again.Under item 2 of the vector i.e. number with 
2 divisors you should get  50847534.The last item of the vector 
is for number with 1344 divisors and there are 4 of them.
After the program is asking :
'You can write the data of the vector to a formatted file in order
 to read them with other editors.Write? Y/N'
For the moment answer No(press emter)
After the program is writing :

 "   Option for a list of numbers with the same number of divisors 
    up to 1000000000
	If N is large and the number of divisors is small the list 
	could be big.
    The program finds  only 2000 numbers as generated
    by the algorithm and sorts them. 
       
	Enter 0 to go to main menu otherwise the number' 
    of divisors of the numbers to be indicated. '
    For instance 6 for a list of numbers with 6 divisors up to N
        
	    Number of divisors ? 	"

      
Enter 1344.
the program tells that there are 4 numbers with 1344 divisors


Press enter again and the sorted list will be indicated.
The program is now asking as above "Write to a file ? " 
enter   No for the moment and you go to the menu.

 

Please do this checking with these same numbers to be  sure that 
the data in the 3 vectors sent with  the program are ok.
For other uses follow the instructions given by the program.
The times indicated are for a PC Pentium 100


Legal
-------
This program is free software and can be copied and used freely 
at your own responsability as long as there are no changes made to it.
It has been written in Fortran and compiled with Microsoft Fortran 
Power Station 4.0
No warranty is granted and the use of the program cannot generate  
obligations,responsability or liabilities of any sort   for me , 
for Microsoft or for anyone else

Ito Buda 
Via S.Vito 5
Trieste
Italy
email ivoito@tin.it  
