640096

Appears in sequences

• 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=46A181368
• Numbers that are abundant (A005101) and have no Zumkeller divisors.at n=31A376879
• Numbers that are primitive non-deficient, but not primitive Zumkeller.at n=17A378656