71981

Appears in sequences

• Number of connected 3-element antichains on a labeled n-set.at n=7A094034
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (0, 1, -1), (1, 0, 0), (1, 0, 1)}.at n=10A149879
• Table read by downward diagonals: T(n,k) = number of skeleta of (3+1)-free posets with n clone sets and k tangles.at n=31A221494