1422564

Appears in sequences

• Number of self-dual monotone Boolean functions of n variables.at n=7A001206
• Number of ways to arrange 4 indistinguishable points on an n X n X n triangular grid so that no four points are in the same row or diagonal.at n=11A194481
• Triangle read by rows: T(n,k) = PIP(n,k) is the number of maximal families of sets from {1,2,...,n} with the property that if A and B are sets in the family, then |AB|>=k.at n=21A248929