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A215868 Number of permutations of 0..floor((n*8-2)/2) on odd squares of an nX8 array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing.

%I A215868 #6 Jul 22 2025 23:25:44
%S A215868 1,14,110,3001,26451,767560,6812794,198409297,1761748159,51317680568,
%T A215868 455678075546,13273519382093,117863060852067,3433253982499552,
%U A215868 30485799411892266,888026282079787049,7885286478349158743
%N A215868 Number of permutations of 0..floor((n*8-2)/2) on odd squares of an nX8 array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing.
%C A215868 Column 8 of A215870
%H A215868 R. H. Hardin, <a href="/A215868/b215868.txt">Table of n, a(n) for n = 1..210</a>
%F A215868 Empirical: a(n) = 272*a(n-2) -3439*a(n-4) -3336*a(n-6) +140*a(n-8)
%e A215868 Some solutions for n=4
%e A215868 ..x..0..x..2..x..4..x..6....x..0..x..1..x..2..x..7....x..0..x..1..x..3..x..5
%e A215868 ..1..x..3..x..7..x..9..x....3..x..4..x..5..x..8..x....2..x..4..x..8..x..9..x
%e A215868 ..x..5..x..8..x.10..x.13....x..6..x.10..x.11..x.12....x..6..x.10..x.12..x.14
%e A215868 .11..x.12..x.14..x.15..x....9..x.13..x.14..x.15..x....7..x.11..x.13..x.15..x
%K A215868 nonn
%O A215868 1,2
%A A215868 _R. H. Hardin_ Aug 25 2012