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A332921 Number of symmetric non-isomorphic free unrooted snake-shaped polyominoes of maximum length on a quadratic board of n X n squares. 3
1, 1, 2, 3, 2, 0, 3, 0, 2, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
Polyominoes only differing by any combination of translation, rotation and reflection are counted only once.
LINKS
EXAMPLE
a(1) = 1 (L = A331968(1) = 1):
X
.
a(2) = 1 (L = 3):
X O
. X
.
a(3) = 2 (L = 7):
X O O . X O
. . O X . O
X O O O O O
.
a(4) = 3 (L = 11)
. X O . . X O O . X O O
X . O O X . . O X . . O
O O . O O . . O O . O O
. O O O O O O O O O O .
.
a(5) = 2 (L = 17)
O O O O X O O O O O
O . . . . O . . . O
O O O O O O O . O O
. . . . O . O . O .
X O O O O X O . O X
.
a(7) = 3 (L = 33)
O O O . O O O O O X . O O O O O O . O O O
O . O . O . O O . . O O . O O . O O O . O
O . O O O . O O O . O . O O O O . . . O O
O O . . . O O . O . O . O . . O O . O O .
. O O . O O . O O . O . O O X . O . O . x
X . O . O . X O . O O . . O O . O . O . O
O O O . O O O O O O . X O O O O O . O O O
.
a(9) = 2 (L = 53)
. O X . O O O O O O O X . O O O O O
O O . O O . . . O O . . O O . . . O
O . O O . O O O O O . O O . O O O O
O . O . O O . . . O . O . O O . . .
O O O . O . O O O O O O . O . . . .
. . . O O . O . O . . . O O . O O O
O O O O . O O . O O O O O . O O . O
O . . . O O . O O O . . . O O . . O
O O O O O . X O . O O O O O . X O O
CROSSREFS
Sequence in context: A324300 A323695 A303121 * A239579 A165192 A104771
KEYWORD
nonn,hard,more
AUTHOR
Hugo Pfoertner, Mar 05 2020
STATUS
approved

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Last modified March 28 04:13 EDT 2024. Contains 371235 sequences. (Running on oeis4.)