
<i>   LFIB4 is an extension of what I have previously
   defined as a lagged Fibonacci generator:
   x(n)=x(n-r) op x(n-s), with the x's in a finite
   set over which there is a binary operation op, such
   as +,- on integers mod 2^32, * on odd such integers,
   exclusive-or(xor) on binary vectors. Except for
   those using multiplication, lagged Fibonacci
   generators fail various tests of randomness, unless
   the lags are very long. (See SWB below).
   To see if more than two lags would serve to overco