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A220560

Number of ways to reciprocally link elements of an nX6 array either to themselves or to exactly one horizontal or antidiagonal neighbor.

13, 481, 16310, 561636, 19333688, 665748170, 22926570957, 789539775889, 27190037181789, 936366170726784, 32246430390993213, 1110497486239608510, 38243137393453789704, 1317011137774021018880, 45355021979509463823738

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OFFSET

1,1

COMMENTS

Column 6 of A220562

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 43*a(n-1) -317*a(n-2) +783*a(n-3) -721*a(n-4) +375*a(n-5) -125*a(n-6) +19*a(n-7) -a(n-8) for n>9

EXAMPLE

Some solutions for n=3 0=self 3=ne 4=w 6=e 7=sw (reciprocal directions total 10)

..0..7..6..4..0..0....6..4..6..4..6..4....0..0..0..7..0..0....0..0..0..7..0..7

..3..0..7..0..6..4....0..0..0..0..7..0....0..7..3..7..6..4....6..4..3..0..3..0

..0..3..0..6..4..0....6..4..0..3..0..0....3..0..3..0..6..4....0..0..0..0..0..0

CROSSREFS

Sequence in context: A012143 A368788 A173403 * A033983 A055412 A196911

Adjacent sequences: A220557 A220558 A220559 * A220561 A220562 A220563

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 16 2012

STATUS

approved

URL: https://oeis.org/A220560

⇱ A220560 - OEIS