Tetrads and their Counting
Juris Čerņenoks, Andrejs Cibulis · Baltic Journal of Modern Computing · 2018
There is no known formula yielding the number of distinct polyominoes of the given number of squares.The same can be said about tetrads made of polyominoes or another polyforms.All n-ominoes up to n = 17 have been checked, the number of tetrads and the number of full tetrads have been determined.Some open problems have been proposed.