A294151 Number of perforated polyominoes with n cells, identifying mirror images.

1, 1, 2, 3, 8, 13, 36, 76, 202, 482, 1281, 3277, 8749, 23083, 62056, 166498, 450576, 1220542, 3321870, 9057388, 24769906

Offset

1,3

Comments

A perforated polyomino is a polyomino in which every cell has at least one even coordinate.

Links

Table of n, a(n) for n=1..21.

Example

a(4)=3 because there are 5 tetrominoes, and the skew and square tetrominoes do not lie in the perforated grid, which leaves 3.

Crossrefs

Cf. A000105, number of polyominoes with n cells; A292065, number of Besźel Polycubes with n cells, distinguishing mirror images; A292157, same but identifying mirror images.

Sequence in context: A317911 A151889 A366020 * A294566 A129873 A025575

Adjacent sequences: A294148 A294149 A294150 * A294152 A294153 A294154

Keyword

nonn,more,hard

Author

George Sicherman, Oct 23 2017

Extensions

a(16) - a(21) from Joerg Arndt, Dec 11 2023

Status

approved