Fig. 1.

Schematic illustration of the three situations considered in Eq. (8). Bold lines represent boundaries between adjacent codons. (a), (b), and (c) are examples of $|\sigma |$ = 4 [$K(\sigma )$ = 2], $|\sigma |$ = 6 [$K(\sigma )$ = 3], and $|\sigma |$ = 5 [$K(\sigma )$ = 3], respectively. From top to bottom, examples for j = 1, j = 2, and j = 3 are shown. Gray boxes indicate the nucleotides of a forbidden motif.