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

0,9

Comments

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

Links

Table of n, a(n) for n=0..33.

Sean A. Irvine, Java program (github)

Formula

Antidiagonal sums of A338210.

Crossrefs

Cf. A001168, A338210, A338213.

Sequence in context: A340692 A234312 A244136 * A337451 A352737 A133168

Adjacent sequences: A338209 A338210 A338211 * A338213 A338214 A338215

Keyword

nonn,more

Author

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

Status

approved