

A331986


Number of snakelike polyominoes with the maximum possible number of unit squares in an n X n square.


6



1, 4, 8, 84, 56, 136, 52, 216, 16, 1504, 2352, 1152, 1344, 123216, 82432, 11008, 308992
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OFFSET

1,2


COMMENTS

The maximum possible number of unit squares is given by A331968(n).
Equivalently, a(n) is the number of maximum length paths without chords in the n X n grid graph. A path without chords is an induced subgraph that is a path.
For n > 1, a(n) is a multiple of 4 since a solution can have at most one symmetry considering rotations and reflections.  Andrew Howroyd, Feb 04 2020


LINKS



EXAMPLE

For n = 4 the number of snakelike polyominoes with 11 cells is 84.


CROSSREFS



KEYWORD

nonn,walk,hard,more


AUTHOR



EXTENSIONS

a(16)a(17) from Yi Yang, Oct 03 2022


STATUS

approved



