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A263366 Number of (n+1) X (1+1) 0..2 arrays with each row and column divisible by 7, read as a base-3 number with top and left being the most significant digits.

%I A263366 #8 Jan 01 2019 20:13:23
%S A263366 1,1,2,5,10,19,37,73,146,293,586,1171,2341,4681,9362,18725,37450,
%T A263366 74899,149797,299593,599186,1198373,2396746,4793491,9586981,19173961,
%U A263366 38347922,76695845,153391690,306783379,613566757,1227133513,2454267026,4908534053
%N A263366 Number of (n+1) X (1+1) 0..2 arrays with each row and column divisible by 7, read as a base-3 number with top and left being the most significant digits.
%H A263366 R. H. Hardin, <a href="/A263366/b263366.txt">Table of n, a(n) for n = 1..210</a>
%F A263366 Empirical: a(n) = 3*a(n-1) - 3*a(n-2) + 3*a(n-3) - 3*a(n-4) + 3*a(n-5) - 2*a(n-6).
%F A263366 Empirical g.f.: x*(1 - 2*x + 2*x^2 - x^3 + x^4 - 2*x^5) / ((1 - x)*(1 - 2*x)*(1 - x + x^2)*(1 + x + x^2)). - _Colin Barker_, Jan 01 2019
%e A263366 All solutions for n=4:
%e A263366 ..2..1....0..0....2..1....0..0....2..1
%e A263366 ..0..0....2..1....0..0....0..0....2..1
%e A263366 ..2..1....0..0....0..0....0..0....0..0
%e A263366 ..0..0....0..0....2..1....0..0....2..1
%e A263366 ..2..1....2..1....0..0....0..0....2..1
%Y A263366 Column 1 of A263373.
%K A263366 nonn
%O A263366 1,3
%A A263366 _R. H. Hardin_, Oct 16 2015