
COMMENTS

Maximal antichains are those which cannot be extended without violating the antichain condition.
This is the breakdown by size of (or number of elements in) the antichains beginning with antichains of size 0 and increasing:
n=0: 0, 1;
n=1: 0, 1;
n=2: 0, 2;
n=3: 0, 3, 1;
n=4: 0, 3, 8, 6;
n=5: 0, 3, 14, 62, 132, 124, 42, 2;
n=6: 0, 3, 21, 157, 983, 4438, 15454, 41827, 79454, 112344, 117259, 88915, 47295, 14909, 3498, 334, 21, 1


EXAMPLE

For n = 3 there are 4 maximal antichains. Assume that the five elements in the D_3 poset are depicted using a Hasse diagram and labeled A through E from bottom to top. Then the 4 maximal antichains are {A}, {B,C}, {D}, {E}.
