General and symmetric rules are specified as a mapping that maps the different neighborhood configurations to 0 and 1. If the neighborhood consists for example of three sites, there are 8 bit necessary to specify the rule. Alternatively, the corresponding number of these 8 bits in the decimal base can be specified. For the table above the number is 30. The right bit in the table is the most significant one.
Totalistic rules map the total number of active cells in the neighborhood to the new state.
If the neighborhood consists for example of 5 sites, there can be 0 to 5 active cells in the neighborhood. The totalistic rule is specified by a mapping that maps the first 6 integers to 0 and 1. For the table above the number is 54. Again, the right bit in the table is the most significant one. Let us illustrate these relationships for 3 neighbor-sites cellular automata.