cp's OEIS Frontend

A215786 Number of permutations of 0..floor((n*8-1)/2) on even squares of an nX8 array such that each row, column, diagonal and (downwards) antidiagonal of even squares is increasing.

%I A215786 #6 Jul 22 2025 23:24:25
%S A215786 1,5,110,932,26451,234217,6812794,60485308,1761748159,15643423061,
%T A215786 455678075546,4046220880948,117863060852067,1046572601513969,
%U A215786 30485799411892266,270700616010831020,7885286478349158743
%N A215786 Number of permutations of 0..floor((n*8-1)/2) on even squares of an nX8 array such that each row, column, diagonal and (downwards) antidiagonal of even squares is increasing.
%C A215786 Column 8 of A215788
%H A215786 R. H. Hardin, <a href="/A215786/b215786.txt">Table of n, a(n) for n = 1..210</a>
%F A215786 Empirical: a(n) = 272*a(n-2) -3439*a(n-4) -3336*a(n-6) +140*a(n-8)
%e A215786 Some solutions for n=4
%e A215786 ..0..x..1..x..3..x..7..x....0..x..1..x..2..x..3..x....0..x..1..x..2..x..5..x
%e A215786 ..x..2..x..4..x..9..x.10....x..4..x..6..x..7..x..8....x..3..x..4..x..7..x.11
%e A215786 ..5..x..6..x.11..x.12..x....5..x..9..x.10..x.12..x....6..x..8..x..9..x.13..x
%e A215786 ..x..8..x.13..x.14..x.15....x.11..x.13..x.14..x.15....x.10..x.12..x.14..x.15
%K A215786 nonn
%O A215786 1,2
%A A215786 _R. H. Hardin_ Aug 23 2012