farey(n):=if n=1 then ["0/1","1/1"] else block(
    create_list([i,j],i,0,n-1,j,1,n),
    map(lambda([x],if x[1]=0 and x[2]#1 then false else if x[1]=x[2] and x[1]#1 then false else if x[1]<=x[2] then x),%%),
    delete(false,%%),
    unique(map(lambda([x],x[1]/x[2]),%%)),
    append(rest(append(["0/1"],rest(%%)),-1),["1/1"])
)$

/* Test cases */
/* Sequences from order 1 through 11 */
farey(1);
farey(2);
farey(3);
farey(4);
farey(5);
farey(6);
farey(7);
farey(8);
farey(9);
farey(10);
farey(11);

/* Length of sequences from order 100 through, 1000 by hundreds */
length(farey(100));
length(farey(200));
length(farey(300));
length(farey(400));
length(farey(500));
length(farey(600));
length(farey(700));
length(farey(800));
length(farey(900));
length(farey(1000));