“…Third, in case we want we use block codes with smaller code words, but having in mind that they would be less efficient, we can search for codes with relative efficiency between and including η 2 and η 4 . These codes have (m, n) ∈ ∪ i=1 ∆ i , we observe that the next more efficient pairs after (13,24) are, in order of decreasing efficiency, the pairs (7,13), (8,15), (9,17), (10,19), (11,21), (12,23), (1,2) and of course their multiples. Their efficiency η = (m/n)/C, including (13,24), in decreasing order are: 99.98%, 99.38%, 98.44%, 97.71%, 97.14%, 96.68%, 96.30% and 92.29%, respectively.…”