12977815

Appears in sequences

• Unlabeled version of A055203: number of different relations between n intervals (of nonzero length) on a line, up to permutation of intervals.at n=7A121316
• Triangle read by rows: number of generic n-rook placements with k rooks below the main diagonal.at n=27A269744
• Array read by antidiagonals: A(n,k) is the number of binary matrices with k columns and any number of nonzero rows with n ones in every column and columns in nonincreasing lexicographic order.at n=47A330942