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 A220623 Number of ways to reciprocally link elements of an 4Xn array either to themselves or to exactly one horizontal, diagonal and antidiagonal neighbor 1

%I

%S 1,71,765,17084,282777,5280827,93905509,1703300073,30648000256,

%T 553256525421,9974206108397,179912817659011,3244530759637569,

%U 58516690759430228,1055339507419304093,19033159346284815815

%N Number of ways to reciprocally link elements of an 4Xn array either to themselves or to exactly one horizontal, diagonal and antidiagonal neighbor

%C Row 4 of A220621

%H R. H. Hardin, <a href="/A220623/b220623.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 14*a(n-1) +98*a(n-2) -452*a(n-3) -102*a(n-4) +876*a(n-5) -144*a(n-6) -268*a(n-7) +22*a(n-8) -8*a(n-9) +15*a(n-10)

%e Some solutions for n=3 0=self 1=nw 3=ne 4=w 6=e 7=sw 9=se (reciprocal directions total 10)

%e ..0..6..4....6..4..0....6..4..0....0..6..4....0..7..0....0..0..7....9..9..0

%e ..0..6..4....6..4..0....0..9..0....0..9..0....3..9..0....0..3..0....0..1..1

%e ..0..7..7....0..0..0....9..0..1....0..0..1....0..0..1....9..7..0....6..4..0

%e ..3..3..0....0..6..4....0..1..0....0..0..0....6..4..0....3..1..0....6..4..0

%K nonn

%O 1,2

%A _R. H. Hardin_ Dec 17 2012

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Last modified June 30 09:10 EDT 2022. Contains 354920 sequences. (Running on oeis4.)