A338212 a(n) is the number of fixed polyominoes with sprawl n.

1, 0, 0, 0, 0, 1, 0, 0, 2, 0, 4, 2, 9, 9, 22, 32, 66, 104, 200, 348, 646, 1172, 2144, 3964, 7285, 13581, 25136, 47070, 87700, 164764, 309308, 582152, 1098698, 2074484

Offset: 0

Author

Sean A. Irvine and Allan C. Wechsler, Oct 17 2020

Keywords

• nonn
• more

Comments

The sprawl of a polyomino is the number of cells in a polyomino plus the number of cells adjacent to it.

Links

• Sean A. Irvine, Java program (github)

Crossrefs

Cf. A001168, A338210, A338213.

Formula

Antidiagonal sums of A338210.