The set of forbidden pattern is

                                  {[1, 3, 2]}

                         This is the (RIGOROUS) scheme

   [{[2, 1], [1, 2]}, {[], [1]}, table([       , table([                   ,
                                     [2, 1] = 1      [] = {[1]}
                                     [1, 2] = 2      [1] = {[2, 1], [1, 2]}
                                 ])              ])

       table([         ]
           [] = {}
           [1] = {}
           [2, 1] = {}
           [1, 2] = {1}
       ])

                              This is the sequence

 [1, 1, 2, 5, 14, 42, 132, 429, 1430, 4862, 16796, 58786, 208012, 742900,

     2674440, 9694845, 35357670, 129644790, 477638700, 1767263190, 6564120420]

                    This is the (Semi-Rigorous) Recurrence

                              2 - 4 n + (1 + n) N