Page "Random sequence" Paragraph 3

Émile Borel was one of the first mathematicians to formally address randomness in 1909.

In 1919 Richard von Mises gave the first definition of algorithmic randomness, which was inspired by the law of large numbers, although he used the term collective rather than random sequence.

Using the concept of the impossibility of a gambling system, von Mises defined an infinite sequence of zeros and ones as random if it is not biased by having the frequency stability property i. e. the frequency of zeros goes to 1 / 2 and every sub-sequence we can select from it by a " proper " method of selection is also not biased.