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A215867 Number of permutations of 0..floor((n*7-2)/2) on odd squares of an n X 7 array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing.

%I A215867 #11 Nov 27 2015 05:43:26
%S A215867 1,5,29,262,1642,15485,97289,918637,5772013,54503318,342457898,
%T A215867 3233726365,20318307913,191859642509,1205501906765,11383190276278,
%U A215867 71523418913482,675374034791837,4243543228336841,40070496565665517
%N A215867 Number of permutations of 0..floor((n*7-2)/2) on odd squares of an n X 7 array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing.
%C A215867 Column 7 of A215870.
%H A215867 R. H. Hardin, <a href="/A215867/b215867.txt">Table of n, a(n) for n = 1..210</a>
%F A215867 Empirical: a(n) = 61*a(n-2) -99*a(n-4) -2*a(n-6).
%F A215867 Empirical: g.f.: -x*(-1 -5*x +32*x^2 +43*x^3 +28*x^4 +2*x^5) / ( 1 -61*x^2 +99*x^4 +2*x^6 ). - _R. J. Mathar_, Nov 27 2015
%e A215867 Some solutions for n=4:
%e A215867 ..x..0..x..2..x..4..x....x..0..x..2..x..4..x....x..0..x..2..x..4..x
%e A215867 ..1..x..3..x..5..x..7....1..x..3..x..5..x..8....1..x..3..x..6..x..8
%e A215867 ..x..6..x..9..x.10..x....x..6..x..9..x.10..x....x..5..x..7..x.10..x
%e A215867 ..8..x.11..x.12..x.13....7..x.11..x.12..x.13....9..x.11..x.12..x.13
%K A215867 nonn
%O A215867 1,2
%A A215867 _R. H. Hardin_, Aug 25 2012