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A200893 Triangle read by rows: number of meanders filling out an n by 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 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,10

COMMENTS

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

LINKS

Table of n, a(n) for n=1..34.

Jon Wild, Illustration for T(5,4) = 14

Jon Wild, Illustration for T(6,4)=63

Jon Wild, Illustration for T(7,4)=224

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).

Sequence in context: A293301 A218453 A186372 * A294583 A283675 A294653

Adjacent sequences:  A200890 A200891 A200892 * A200894 A200895 A200896

KEYWORD

nonn,tabl

AUTHOR

Jon Wild, Nov 23 2011

STATUS

approved

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Last modified February 25 03:40 EST 2018. Contains 299630 sequences. (Running on oeis4.)