Template:3-bit Walsh permutation/inverse nitpick



To be precise, the group consists of the 168 binary matrices whose inverses are integer matrices, namely with entries 0, 1 and &minus;1. Not part of the group are the six matrices whose inverses do not contain integers:

The following Python script shows that the 512 binary matrices consist of 338 singular matrices, 168 with integer inverses and 6 with non-integer inverses: