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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 1
13, 481, 16310, 561636, 19333688, 665748170, 22926570957, 789539775889, 27190037181789, 936366170726784, 32246430390993213, 1110497486239608510, 38243137393453789704, 1317011137774021018880, 45355021979509463823738 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 6 of A220562
LINKS
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
KEYWORD
nonn
AUTHOR
R. H. Hardin Dec 16 2012
STATUS
approved

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Last modified March 1 05:24 EST 2024. Contains 370430 sequences. (Running on oeis4.)