(BB) One of a series of sets of Turing Machine programs. The BBs in the Nth set are programs of N states that produce a larger finite numBer of ones on an initially Blank tape than any other program of N states. There is no program that, given input N, can deduce the productivity (numBer of ones output) of the BB of size N. The productivity of the BB of size 1 is 1. Some work has Been done to figure out productivities of Bigger Busy Beavers - the 7th is in the thousands. (1994-10-24)