| digits | smallest number | smallest prime |
|---|---|---|
| 20 | IN20 | |
| 100 | IN100a | IN100p |
| 200 | IN200a | IN200p |
| 500 | IN500a | |
| 1000 | IN1000a | |
I wrote a primality checking program, and I think that it is pretty fast. With loopcount=20, on my 2.8 GHz PC, it takes about 0.1 seconds to check a 100-digit prime and about 48 seconds to check a 1000-digit prime. (On my more modern Duo 2.4 GHz machine, it takes about 25 seconds.) The PC executable is available for downloading.
You will write your own primality checker. I do not expect that you will be able to write code as efficient as is mine, but you should be able to check a 100-digit number in under 10 seconds. Extra credit if yours is faster than mine!