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Number of (n+1)X(2+1) 0..2 arrays with no element greater than all horizontal neighbors or less than all vertical neighbors
1

%I #4 Feb 24 2014 07:51:32

%S 9,67,376,1867,9489,50232,267174,1408341,7395987,38886701,204722786,

%T 1077853232,5673085286,29856142160,157133586571,827031030519,

%U 4352855509300,22909846720541,120578232671314,634623931681625

%N Number of (n+1)X(2+1) 0..2 arrays with no element greater than all horizontal neighbors or less than all vertical neighbors

%C Column 2 of A238323

%H R. H. Hardin, <a href="/A238317/b238317.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) -12*a(n-2) +39*a(n-3) +6*a(n-4) +62*a(n-5) +49*a(n-6) +33*a(n-7) -32*a(n-8) -41*a(n-9) -12*a(n-10) +6*a(n-11) +5*a(n-12) +a(n-13)

%e Some solutions for n=5

%e ..2..2..1....1..1..1....0..1..1....1..1..1....2..2..2....1..2..2....0..2..2

%e ..1..1..1....1..1..1....0..0..0....0..0..0....0..0..0....0..0..0....0..2..2

%e ..1..1..1....2..2..0....0..0..0....0..0..0....0..0..0....0..0..0....2..2..1

%e ..1..1..0....1..1..0....0..2..2....2..2..0....0..0..0....0..1..1....0..0..0

%e ..1..1..0....0..1..1....0..2..2....2..2..2....0..1..1....1..2..2....0..0..0

%e ..1..2..2....0..2..2....0..2..2....2..2..2....1..1..1....2..2..2....2..2..1

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 24 2014