The article is devoted to the study of groups generated by automata with three states over an alphabet with two letters. It is shown that this class of groups contains no more than 124 pairwise non-isomorphic groups, does not contain infinite periodic groups, and contains a unique free non-abelian group. All finite and abelian groups in this class are described. Information about short relations, the size of factors, the initial values of the growth function, and the histogram of the spectral density of the Schreier graph of 9th level for 11 chosen groups is presented. In some cases we give a picture of the limit space.

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