**1.** A sequence of numbers that has been computed by some defined arithmetic process but is effectively a random number sequence for the purpose for which it is required.

*Note:* Although a pseudorandom number sequence in this sense often appears to lack any definite pattern, any pseudorandom number generator with a finite internal state will repeat after a very long sequence of numbers. This can be proved using the pigeonhole principle.

*see also* Pseudorandom number generator.

Source: originally from Federal Standard 1037C and from MIL-STD-188