Keep in mind that the VBA Rnd() function has a cycle of just 16.7
million random numbers. (At least, that was the case in Excel
2002).

If you need more than 16.7 million random numbers for an application,
as I did, you will need to create the numbers with another
algorithm. I settled on the Mersenne Twister algorithm, which,
thankfully, is pretty efficient!

See: www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html