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On Fri, 24 May 2013 17:20:40 +1000
Vaughan McAlley <> wrote:

> On 24 May 2013 17:14, Michal Kottman <> wrote:
> > For this small test case, it generates 252 number. For your case,
> > C(25,40) == 40225345056, which is over 40 billion numbers. Would
> > you like to rethink your original problem?
> I have a Raspberry Pi that can chug away for a couple of weeks, so it
> might be doable. Looks like I might need to put my C programmer’s hat
> on... thanks for all the suggestions!

IIRC, my prime number generator produced the first 2 billion primes in
a few hours, so I agree this isn't undoable.

You'll need some way of accepting and storing the numbers that come out
of this -- they might overrun your hard disk. 

One comment about all the algorithms delivering the next number with Y
number of 1's: I'm pretty sure those work on the natural hardware size
of numbers on a given computer, so unless your hardware has 40 bit
integers, I don't think those will work, at least not without some

One more thing -- make sure your computer has plenty of cooling
capacity. My prime number generator got my CPU up to 86 Celsius in
maybe 5 minutes.


Steve Litt                *
Troubleshooting Training  *  Human Performance