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Number of nX2 0..4 arrays with each element equal to the number its horizontal and vertical neighbors less than or equal to itself
1

%I #5 Mar 31 2012 12:36:26

%S 3,23,56,461,2897,17967,116911,757146,4893755,31718101,205477601,

%T 1331145835,8624488786,55876739813,362017883823,2345474974395,

%U 15196064614313,98453588371088,637869800997933,4132686977034097

%N Number of nX2 0..4 arrays with each element equal to the number its horizontal and vertical neighbors less than or equal to itself

%C Column 2 of A196544

%H R. H. Hardin, <a href="/A196538/b196538.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 3*a(n-1) +22*a(n-2) +24*a(n-3) -86*a(n-4) -296*a(n-5) -126*a(n-6) +428*a(n-7) +420*a(n-8) +239*a(n-9) +92*a(n-10) -147*a(n-11) +22*a(n-12) +26*a(n-13) -13*a(n-14) +5*a(n-15)

%e Some solutions for n=4

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

%e ..2..1....3..3....3..3....0..3....2..3....0..2....2..3....2..3....0..1....2..3

%e ..3..2....1..2....2..1....3..3....2..3....2..3....0..2....0..2....3..3....0..2

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Oct 03 2011