The last table of Resistor network topic of "mathworld" made me in doubt on R=3 & R=4
As the table give only 4 possible value for N=3, but the sequence is 8.
I try to dig out and found they are actually have all possible valve = 8 i.e.
6/11, 5/6, 4/3, 3/2, 11/5, 11/4, 11/3, 6
(underline additional values)