

A200893


Triangle read by rows: number of meanders filling out an n X k grid.


4



1, 0, 1, 0, 1, 0, 0, 1, 1, 4, 0, 1, 1, 14, 42, 0, 1, 3, 63, 843, 9050, 0, 1, 3, 224, 7506, 342743, 6965359, 0, 1, 8, 1022, 71542, 6971973
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OFFSET

1,10


COMMENTS

The sequence counts the distinct closed paths that visit every cell of an nbyk rectangular lattice at least once, that never cross any edge between adjacent squares more than once, and that do not selfintersect. Paths related by rotation and/or reflection of the square lattice are not considered distinct.


LINKS



FORMULA

T(n,3) appears to be equal to A090597.


EXAMPLE

The 14 solutions for (n,k)=(5,4), 63 solutions for (n,k)=(6,4) and 224 solutions for (n,k)=(7,4) are illustrated in the supporting png files.


CROSSREFS

Cf. A200000 (sequence of entries for square grid).


KEYWORD



AUTHOR



STATUS

approved



