\\ cx -> xc S(v) = concat(v[2..#v], v[1]) \\ inverse of S S_1(v) = concat(v[#v], v[1..#v-1]) phi1(h) = { my (v=[0,0]); for (k=1, h, v=phi(v); ); concat(S_1(v), [h+1]) } phi(v) = { concat(apply(phi1, v)) } { v = [0]; for (k=1, 5, v = phi(v); ); for (n=1, #v, print (n-1 " " v[n]); ); } quit