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A126764 Number of L-convex polyominoes with n cells, that is, convex polyominoes where any two cells can be connected by a path internal to the polyomino and which has at most 1 change of direction (i.e., one of the four orientation of the letter L). 2
1, 1, 2, 6, 15, 35, 76, 156, 310, 590, 1098, 1984, 3515, 6094, 10398, 17434, 28837, 47038, 75820 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..18.

G. Castiglione, A. Frosini, E. Munarini, A. Restivo and S. Rinaldi, Combinatorial aspects of L-convex polyominoes, European J. Combin. 28 (2007), no. 6, 1724-1741.

FORMULA

The reference gives a generating function.

CROSSREFS

Cf. A000105, A003480, A126765.

Sequence in context: A073838 A014303 A076060 * A272340 A090982 A153517

Adjacent sequences:  A126761 A126762 A126763 * A126765 A126766 A126767

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, based on email from Simone Rinaldi (rinaldi(AT)unisi.it), Feb 23 2007

EXTENSIONS

Definition corrected at suggestion of Emeric Deutsch, Mar 03 2007

STATUS

approved

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Last modified February 21 02:02 EST 2020. Contains 332086 sequences. (Running on oeis4.)