A220743 Number of ways to reciprocally link elements of an 6 X n array either to themselves or to exactly two horizontal, diagonal and antidiagonal neighbors, without consecutive collinear links.

1, 32, 949, 45421, 2027456, 94226589, 4335687696, 201959426140, 9355392933041, 434476062233061, 20160870899222101, 935844654794161538, 43434200828618562852, 2016001500367387183289, 93570090322331503458132

Offset

1,2

Comments

Row 6 of A220738.

Links

R. H. Hardin, Table of n, a(n) for n = 1..50

Example

Some solutions for n=3 0=self 1=nw 3=ne 4=w 6=e 7=sw 9=se (reciprocal directions total 10).
.69.49.00...00.00.00...00.67.47...00.67.47...00.00.00...69.49.00...00.79.00
.69.14.17...69.49.00...36.34.00...36.34.00...69.47.00...69.14.17...39.00.17
.00.13.00...00.16.14...00.79.00...00.69.47...39.16.47...00.13.00...00.13.00
.00.67.47...00.79.00...39.69.14...00.39.17...00.13.00...00.00.00...00.79.00
.39.39.00...36.49.17...00.16.14...00.36.14...00.00.00...69.47.00...39.67.14
.00.16.14...00.36.14...00.00.00...00.00.00...00.00.00...36.14.00...36.14.00

Crossrefs

Cf. A220738.

Sequence in context: A227441 A067820 A263818 * A115612 A281342 A298285

Adjacent sequences: A220740 A220741 A220742 * A220744 A220745 A220746

Keyword

nonn

Author

R. H. Hardin Dec 18 2012

Status

approved