A pseudorandom sequence of numbers is one that appears to be statistically random, despite having been produced by a completely deterministic and repeatable process.
[1] Pseudorandom number generators are often used in computer programming, as traditional sources of randomness available to humans (such as rolling dice) rely on physical processes not readily available to computer programs, although developments in hardware random number generator technology have challenged this.
Some notable exceptions are radioactive decay and quantum measurement, which are both modeled as being truly random processes in the underlying physics.
[3] In some cases where it is important for the sequence to be demonstrably unpredictable, physical sources of random numbers have been used, such as radioactive decay, atmospheric electromagnetic noise harvested from a radio tuned between stations, or intermixed timings of keystrokes.
Before modern computing, researchers requiring random numbers would either generate them through various means (dice, cards, roulette wheels,[5] etc.)
In 1947, the RAND Corporation generated numbers by the electronic simulation of a roulette wheel;[5] the results were eventually published in 1955 as A Million Random Digits with 100,000 Normal Deviates.