Hi I am doing experiments with large primes, in particular looking at primes that remain primes when n digits are truncated from the left. For example 6391373 391373 91373 1373 373 73 3 remains prime at each step.
The largest of these in base 10 is 357686312646216567629137. I wrote the following code in preparation for further investigation but I find that the 24 digit number above is not handled as I wish it to be, as you will see below. What have I missed? Thanks digits "."0@": ltrunc 3 : 0"0 0 0 n=: ": 0, }. digits y x: ". n-. ' ' ) NB. Works fine with 7 digit number... ltrunc^:a: 6391373 6391373 391373 91373 1373 373 73 3 0 NB. But I can’t get it working for a 24 digit number! ltrunc 357686312646216567629137 0 0 5 7 6 8 6 0 2 3 ltrunc 357686312646216567629137x 57686312646216568012800 ltrunc x:357686312646216567629137x 57686312646216568012800 Is there a way around the limit? ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
