A359661 a(n) is the number of free convex polyominoes of n cells.

1, 1, 2, 5, 11, 29, 72, 191, 478, 1211, 2973, 7274, 17455, 41645, 98271, 230848, 539000, 1254936

Offset

1,3

Comments

A convex polyomino is such that any vertical or horizontal line connecting two points within the polyomino remains completely within the polyomino.

It has a perimeter of length equal to that of its enclosing rectangle.

A polyomino is convex if and only if (i) it is a board-pile polyomino and (ii) rotated 90 degrees it is still a board-pile-polyomino.

Links

Table of n, a(n) for n=1..18.

Crossrefs

Cf. A000105, A001169, A067675.

Sequence in context: A309857 A117719 A355516 * A316769 A192785 A334578

Adjacent sequences: A359658 A359659 A359660 * A359662 A359663 A359664

Keyword

nonn,more

Author

John Mason, Jan 10 2023

Status

approved