Several computational methods for random number generation exist, but often fall short of the goal of true randomness — though they may meet, with varying success, some of the statistical tests for randomness intended to measure how unpredictable their results are (that is, to what degree their patterns are discernible).
in programming:-
These cannot be random numbers because they're produced by a computer algorithm; computers are physically incapable of randomness. But perhaps sufficiently random for practical purposes is enough.