the increasing sequence of fractions in which numerator and denominator have no common divisor other than one and in which the denominator is less than or equal to a given positive integer p. For p = 4, the Farey sequence of order 4 is 0/1, 1/4, 1/3, 1/2, 2/3, 3/4, 1/1.
Origin of Farey sequence
after English mathematician John Farey (1766-1826), who proposed the terms of the sequence in 1816