A376496 The number of free kissing polyominoes with n cells.

0, 0, 0, 0, 0, 0, 1, 5, 35, 179, 909, 4287, 19723, 88240, 388260, 1683998, 7227374, 30750236

Offset: 1

Author

John Mason, Sep 25 2024

Keywords

• nonn
• more

Comments

A polyomino is 'kissing' if there exist two cells that touch only at a corner such that no cell exists touching both edgewise simultaneously.

The sequence differs from A359520 (Number of free holey polyominoes of n cells with simply-connected interiors) at a(12) because of:

OOOO OOO

O O O O OO

OOOOO OO O

OOO

which are kissing (and hence holey) but do not have simply-connected interiors.

Crossrefs

Cf. A367557, A359520.