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A186877 Number of (n+2) X 7 0..3 arrays with every 3 X 3 subblock commuting with each horizontal and vertical neighbor 3 X 3 subblock. 1

%I

%S 104701,14221,28984,100600,214264,230224,260584,310528,410080,683224,

%T 1122832,1759144,3352075,5594230,8725153,15545365,25632073,40294021,

%U 70802629,117837190,187990240,326143906,544135555,875468515,1502329147

%N Number of (n+2) X 7 0..3 arrays with every 3 X 3 subblock commuting with each horizontal and vertical neighbor 3 X 3 subblock.

%C Column 5 of A186881.

%H R. H. Hardin, <a href="/A186877/b186877.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 2*a(n-1) - a(n-2) + 3*a(n-3) - 6*a(n-4) + 3*a(n-5) + 3*a(n-6) - 3*a(n-7) for n>13.

%F Empirical g.f.: x*(104701 - 195181*x + 105243*x^2 - 257250*x^3 + 627591*x^4 - 413433*x^5 - 470262*x^6 + 164880*x^7 + 298431*x^8 - 84456*x^9 - 233280*x^10 + 344763*x^12) / ((1 - x)*(1 - x - 3*x^3 + 3*x^4 - 3*x^6)). - _Colin Barker_, Apr 20 2018

%e Some solutions for 4 X 7:

%e ..0..0..0..0..0..2..0....2..0..0..0..0..0..2....0..0..0..0..0..2..1

%e ..0..0..0..0..0..0..0....0..0..0..0..0..0..2....2..0..0..0..0..0..2

%e ..1..0..0..0..0..0..0....0..0..0..0..0..0..0....3..2..0..0..0..0..0

%e ..1..2..0..0..0..0..0....0..2..0..0..0..0..0....0..3..2..0..0..0..0

%Y Cf. A186881.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 28 2011

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Last modified October 16 03:28 EDT 2019. Contains 328040 sequences. (Running on oeis4.)