1836550

Appears in sequences

• Let P(A) be the power set of an n-element set A. Then a(n) = the number of pairs of elements {x,y} of P(A) for which either 0) x and y are disjoint and for which either x is a subset of y or y is a subset of x, or 1) x and y are intersecting but for which x is not a subset of y and y is not a subset of x.at n=11A134018
• Number of 2 X n 0..3 arrays with antidiagonals unimodal and rows and diagonals nondecreasing.at n=21A223962