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A198899 Number of n X n 0..4 arrays with values 0..4 introduced in row major order and no element equal to any horizontal or vertical neighbor.

%I A198899 #11 Jul 22 2025 13:06:24
%S A198899 1,4,1211,6907736,423503301834,274342896958292170,
%T A198899 1877611081501313948217870,135766460737448561825230968357842
%N A198899 Number of n X n 0..4 arrays with values 0..4 introduced in row major order and no element equal to any horizontal or vertical neighbor.
%C A198899 Diagonal of A198906
%H A198899 Jean-François Alcover, <a href="/A198899/b198899.txt">Table of n, a(n) for n = 1..14</a>
%e A198899 Some solutions with values 0 to 4 for n=4
%e A198899 ..0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1
%e A198899 ..1..2..1..0....1..2..1..2....1..2..1..2....1..0..2..0....1..0..1..0
%e A198899 ..0..1..3..4....2..3..0..1....3..0..2..0....3..4..0..3....2..1..0..3
%e A198899 ..3..2..0..3....4..1..2..4....4..3..1..3....2..1..2..4....1..4..1..2
%t A198899 A198906 = Cases[Import["https://oeis.org/A198906/b198906.txt", "Table"], {_, _}][[All, 2]];
%t A198899 a[n_] := A198906[[2 n^2 - 2 n + 1]];
%t A198899 Table[a[n], {n, 1, 14}] (* _Jean-François Alcover_, Sep 23 2019 *)
%K A198899 nonn
%O A198899 1,2
%A A198899 _R. H. Hardin_ Oct 31 2011