A220717 Number of ways to reciprocally link elements of an nX6 array either to themselves or to exactly two king-move neighbors, without consecutive collinear links

1, 1930, 201598, 63806966, 14158198781, 3503850286857, 837962999003819, 202559596688263771, 48800208840366180607, 11769507869511009093649, 2837567849598052498110938, 684198360972218804926155379

Offset

1,2

Comments

Column 6 of A220718

Links

R. H. Hardin, Table of n, a(n) for n = 1..31

Example

Some solutions for n=3 0=self 1=nw 2=n 3=ne 4=w 6=e 7=sw 8=s 9=se (reciprocal directions total 10)
.00.00.68.48.00.78...00.67.48.68.49.00...00.68.49.79.79.00...00.69.49.00.78.00
.69.48.29.27.36.24...36.48.27.27.67.14...00.26.34.13.18.17...00.79.17.13.27.78
.00.12.36.14.00.00...00.23.36.34.00.00...00.00.00.00.23.00...36.34.16.34.36.24

Crossrefs

Sequence in context: A253337 A200435 A252108 * A162386 A283925 A166393

Adjacent sequences: A220714 A220715 A220716 * A220718 A220719 A220720

Keyword

nonn

Author

R. H. Hardin Dec 18 2012

Status

approved