<programming> One of a sequence of numbers generated by some
algorithm so as to have an even distribution over some range
of values and minimal correlation between successive
values.

Pseudorandom numbers are used in simulation and
encryption. They are pseudorandom not random because the
sequence eventually repeats exactly and is entirely determined
by the initial conditions.

One of the simplest algorithms is

x[i+1] = (a * x[i] + c) mod m

but this repeats after at most m numbers and successive
numbers are closely related. Better algorithms generally use
more previous numbers to calculate the next number.