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A213375 Irregular array T(n,k) of numbers/2 of non-extendable (complete) non-self-adjacent simple paths of each length within a square lattice bounded by rectangles with nodal dimensions n and 5, n >= 2. 8
4, 4, 6, 10, 10, 2, 4, 8, 16, 22, 42, 24, 42, 22, 18, 4, 8, 20, 40, 72, 80, 90, 66, 184, 72, 236, 26, 4, 8, 20, 44, 100, 136, 220, 156, 348, 244, 800, 336, 1308, 248, 56, 4, 8, 20, 44, 106, 172, 322, 410, 612, 602, 1462, 1122, 3240, 1712, 4682, 1394, 706, 218, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

The irregular array of numbers is:

...k..3....4....5....6....7....8....9...10...11...12...13...14...15...16....17...18....19...20...21...22...23...24

.n

.2....4....4....6...10...10....2

.3....4....8...16...22...42...24...42...22...18

.4....4....8...20...40...72...80...90...66..184...72..236...26

.5....4....8...20...44..100..136..220..156..348..244..800..336.1308..248....56

.6....4....8...20...44..106..172..322..410..612..602.1462.1122.3240.1712..4682.1394...706..218...4

where k is the path length in nodes. In an attempt to define the irregularity of the array, it appears that the maximum value of k is 3n+2 for 2 <= n <= 5, 3n+3 for 6 <= n <= 9 and 3n+4 for n >= 10. Reading this array by rows gives the sequence. One half of the numbers of paths constitute the sequence to remove the effect of the bilateral symmetry of the rectangle.

LINKS

Table of n, a(n) for n=2..62.

C. H. Gribble, Computed characteristics of complete non-self-adjacent paths in a square lattice bounded by various sizes of rectangle.

C. H. Gribble, Computes characteristics of complete non-self-adjacent paths in square and cubic lattices bounded by various sizes of rectangle and rectangular cuboid respectively.

EXAMPLE

T(2,3) = One half of the number of complete non-self-adjacent simple paths of length 3 nodes within a square lattice bounded by a 2 X 5 node rectangle.

CROSSREFS

Cf. A213106, A213249, A213274, A213089, A213342.

Sequence in context: A128037 A102414 A127799 * A226834 A098052 A098530

Adjacent sequences:  A213372 A213373 A213374 * A213376 A213377 A213378

KEYWORD

nonn,tabf

AUTHOR

Christopher Hunt Gribble, Jun 10 2012

STATUS

approved

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Last modified November 22 05:55 EST 2019. Contains 329388 sequences. (Running on oeis4.)