There all together, 2, different equivalence classes For the equivalence class of patterns, {{[3, 2, 1]}, {[1, 2, 3]}} the member , {[3, 2, 1]}, has a scheme of depth , 2 here it is: {[[], {}, {}], [[1], {}, {}], [[2, 1], {[1, 0, 0]}, {2}], [[1, 2], {}, {1}]} Using the scheme, the first, , 31, terms are [1, 1, 2, 5, 14, 42, 132, 429, 1430, 4862, 16796, 58786, 208012, 742900, 2674440, 9694845, 35357670, 129644790, 477638700, 1767263190, 6564120420, 24466267020, 91482563640, 343059613650, 1289904147324, 4861946401452, 18367353072152, 69533550916004, 263747951750360, 1002242216651368, 3814986502092304] This enumerating sequence seems to have the 2 (1 + 2 n) annihilating operator , - ----------- + N 2 + n For the equivalence class of patterns, {{[1, 3, 2]}, {[2, 1, 3]}, {[2, 3, 1]}, {[3, 1, 2]}} the member , {[1, 3, 2]}, has a scheme of depth , 2 here it is: {[[], {}, {}], [[1], {}, {}], [[2, 1], {}, {1}], [[1, 2], {[0, 1, 0]}, {1}]} Using the scheme, the first, , 31, terms are [1, 1, 2, 5, 14, 42, 132, 429, 1430, 4862, 16796, 58786, 208012, 742900, 2674440, 9694845, 35357670, 129644790, 477638700, 1767263190, 6564120420, 24466267020, 91482563640, 343059613650, 1289904147324, 4861946401452, 18367353072152, 69533550916004, 263747951750360, 1002242216651368, 3814986502092304] This enumerating sequence seems to have the 2 (1 + 2 n) annihilating operator , - ----------- + N 2 + n Out of a total of , 2, cases 2, were successful and , 0, failed Success Rate: , 1. Here are the failures {} {} It took, 4.044, seconds of CPU time .