67820

Appears in sequences

• a(n) = (2*n^3 + 5*n^2 - 9*n)/2.at n=39A162258
• Triangle read by rows: T(n,k) is the number of L-convex polyominoes of semiperimeter n, having k maximal rectangles (n >= 2, 1 <= k <= floor(n/2)). An L-convex polyomino is a convex polyomino in which any two cells can be connected by a path internal to the polyomino and which has at most 1 change of direction (i.e., one of the four orientations of the letter L). A maximal rectangle in an L-convex polyomino P is a rectangle included in P that is maximal with respect to inclusion.at n=33A181368
• Number of n-step three-sided prudent self-avoiding walks.at n=11A191823
• Sum T(n,k) of the k-th entries in all blocks of all set partitions of [n]; triangle T(n,k), n>=1, 1<=k<=n, read by rows.at n=39A285595
• Triangle read by rows: T(n,k) is the number of 4-dimensional balanced ballot paths of 4n steps such that the height is exactly k, 3 <= k <= 3*n.at n=37A387987