HP41C random number generator help

[ttw]

For calculators with 12 digits of precision, the following exact method will work (though the cycle is only 999,958). I can post a modification (which does double the time) to double the cycle length (though not the precision) later.

The seed is any non-zero integer.

Recurrence: X(i) = X(i-1) * 423621 mod 999959.
X(i)/999959. Will be uniformly distributed on the open interval (0-1).