At the web site that you reference, the first set of taps listed for the 5 stage LFSR (http://www.newwaveinstruments.com/resources/articles/m_sequence_linear_feedback_shift_register_lfsr/5stages.txt) is `[5, 3]`, so the `_mls_taps[5]` should be `[3]`.  (Both sets of taps are valid; one sequence is a shifted and reversed version of the other.)