Partially directed animals with a bounded number of holes

We address the problem of the exhaustive generation of a particular class of polyominoes, corresponding to partially directed animals with a bounded number of holes. We apply an approach based on discrete dynamical systems to develop an algorithm that generates each polyomino in constant amortized time and space O(n). By implementing the algorithm in C++ we have obtained new sequences that do not appear in the On-Line Encyclopedia of Integer Sequences.