(11C) Random Prime Number Generator

[Dieter]

(10-21-2018 03:22 AM)Gamo Wrote:  Sure do, I like to see the update version.

OK - but this is not as sophisticated as the program Thomas posted. ;-)

For four-digit prime numbers your program requires two changes.
First change the program start this way:

Code:

LBL E
RAN#
4500
x 
INT
2
x
1001
+
STO 0

This generates an odd random number between 1001 and 9999. Take a closer look at how it works: first a random integer between 0 and 4499 is generated. Then this is doubled, which yields an even integer between 0 and 8998. Finally 1001 is added, resulting in an odd random integer between 1001 and 9999.

Note: due to roundoff issues the largest prime candidate can be 10001. But since 10001 is not a prime number it will not be returned.

Finally remove the complete LBL 3 part at the end. This seems to be left from another prime number program. Replace the "GTO 3" line with "GTO E".

After these changes the program will generate four-digit random integers.

Dieter