I was bored and found a HP-27S

[Dave Britten]

(06-10-2014 10:38 PM)Don Shepherd Wrote:  

(06-10-2014 08:46 PM)Dave Britten Wrote:  They even managed to port my favorite prime factoring algorithm

Dave, here is a simple prime factoring program for the 17b/17bii solver that I wrote a few years ago. It is a lot faster than the one in the manual because it terminates the loop early by doing a divide by 0. Enter the number to factor and press N, then press FACT. If it beeps and says "Solution Not Found", it has found a factor; RCL FACT to see it. Then press FACT again to see the next (and subsequent) factors. If it doesn't beep, it has found the final factor.

It's not elegant, but it works!

Code:


IF(MOD(N:2)=0:L(FACT:2)+L(N:N/2)/0:SIGMA(I:3:SQRT(N):2:IF(MOD(N:I)=0:L(FACT:I)+L(N:N/I)/0:0))+N)-FACT

EDIT: Never mind, I found my error. Works nice!