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A198716 Number of n X n 0..6 arrays with values 0..6 introduced in row major order and no element equal to any horizontal or vertical neighbor.

%I A198716 #19 Jul 22 2025 01:19:07
%S A198716 1,4,2027,173549032,601755060211186,56817439251356046537693,
%T A198716 143258513960209594417739070314380,
%U A198716 9642423210031999968965088302478619142184723,17325184073281687394967689689039757737268207918711712613,830989324900948864881160725155158690837481885610384662473963254527609
%N A198716 Number of n X n 0..6 arrays with values 0..6 introduced in row major order and no element equal to any horizontal or vertical neighbor.
%H A198716 Jean-François Alcover, <a href="/A198716/b198716.txt">Table of n, a(n) for n = 1..13</a>
%e A198716 Some solutions with all values 0 to 6 for n=4
%e A198716 ..0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1
%e A198716 ..2..3..1..0....2..3..1..0....2..3..1..0....2..3..1..0....2..3..1..0
%e A198716 ..4..5..2..4....4..0..5..2....0..1..4..3....4..1..0..5....4..2..0..5
%e A198716 ..6..0..6..1....6..4..6..0....1..5..3..6....1..6..2..1....3..1..6..1
%t A198716 A198723 = Cases[Import["https://oeis.org/A198723/b198723.txt", "Table"], {_, _}][[All, 2]];
%t A198716 a[n_] := A198723[[2 n^2 - 2 n + 1]];
%t A198716 Table[a[n], {n, 1, 13}] (* _Jean-François Alcover_, Sep 23 2019 *)
%Y A198716 Diagonal of A198723.
%K A198716 nonn
%O A198716 1,2
%A A198716 _R. H. Hardin_, Oct 29 2011
%E A198716 More terms from _Jean-François Alcover_, Sep 23 2019