A359519 Number of free polyominoes of n cells with multiply-connected interiors.

0, 0, 0, 0, 0, 0, 0, 1, 2, 16, 70, 378, 1772, 8456, 38623, 174400, 771944, 3378937

Offset

1,9

Links

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

Formula

a(n) = A000105(n) - A342537(n) (all free polyominoes minus simply-connected interior polyominoes).

Example

a(8) = 1 because of:
OOO
O O
OOO

Crossrefs

Cf. A000104, A000105, A001419, A342537, A359520.

Sequence in context: A034579 A006733 A034580 * A209538 A006729 A007758

Adjacent sequences: A359516 A359517 A359518 * A359520 A359521 A359522

Keyword

nonn,more

Author

John Mason, Jan 04 2023

Status

approved