A373635 Number of free n-celled polyominoes to which two inequivalent cells can be adjoined such that the two resulting free (n+1)-celled polyominoes are identical.

0, 0, 0, 0, 1, 1, 0, 0, 4, 6, 2, 0, 17, 29

Offset

1,9

Comments

Two cells that can be adjoined to an n-celled polyomino are equivalent if there is an isomorphism between the two resulting (n+1)-celled polyominoes that maps the adjoined cell of the first to the adjoined cell of the second.

Links

Table of n, a(n) for n=1..14.

Pontus von Brömssen, Illustration up to n = 11.

Index entries for sequences related to polyominoes.

Example

The smallest example is the P pentomino shown below. The two free hexominoes obtained by adjoining one of the two cells marked "*" are identical, but there is no isomorphism between them that also maps the marked cell of the first to the marked cell of the second.
    _ _
  *|   |
   |  _|*
   |_|

Crossrefs

Cf. A255890, A367758, A373636, A373637.

Sequence in context: A016491 A347052 A375366 * A160327 A124259 A214549

Adjacent sequences: A373632 A373633 A373634 * A373636 A373637 A373638

Keyword

nonn,more

Author

Pontus von Brömssen, Jun 13 2024

Status

approved