|
%I #8 Dec 02 2018 07:15:06
%S 812,3066,9566,24932,73826,231254,718514,2208224,6786900,20903022,
%T 64397300,198324482,610719174,1880738882,5791972896,17837010452,
%U 54930710846,169164213764,520957422434,1604338505654,4940713885010
%N Number of (n+2) X (3+2) 0..2 arrays with every 3 X 3 subblock row and column sum 2 3 or 4 and every diagonal and antidiagonal sum not 2 3 or 4.
%H R. H. Hardin, <a href="/A252223/b252223.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) - a(n-2) + 3*a(n-3) + 3*a(n-4) - a(n-5) - a(n-6) for n>8.
%F Empirical g.f.: 2*x*(406 + 315*x + 590*x^2 - 1568*x^3 - 1519*x^4 - 1188*x^5 - 519*x^6 + 147*x^7) / ((1 - x + 2*x^2 - x^3)*(1 - 2*x - 3*x^2 - x^3)). - _Colin Barker_, Dec 02 2018
%e Some solutions for n=4:
%e ..2..0..2..0..1....2..0..2..1..1....1..0..2..0..1....1..2..1..1..1
%e ..0..2..0..2..0....0..2..0..2..0....1..2..0..2..1....1..0..2..0..1
%e ..2..0..2..0..1....2..0..2..0..1....2..0..2..0..1....0..2..0..2..0
%e ..0..2..0..2..1....0..2..0..2..1....0..2..0..2..0....1..0..2..0..2
%e ..2..0..2..0..1....2..0..2..0..2....2..0..2..0..2....1..2..0..2..1
%e ..1..2..0..1..1....1..2..0..1..1....1..1..1..2..1....2..0..2..1..1
%Y Column 3 of A252228.
%K nonn
%O 1,1
%A _R. H. Hardin_, Dec 15 2014
| 