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A235241 Number of (n+1) X (1+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 6, with no adjacent elements equal (constant stress tilted 1 X 1 tilings). 1

%I

%S 210,906,3746,16150,66874,288510,1195458,5161934,21400266,92486622,

%T 383623154,1659369022,6886195834,29811968622,123773981922,

%U 536299705358,2227615662378,9660029955390,40141785286994,174215753195230

%N Number of (n+1) X (1+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 6, with no adjacent elements equal (constant stress tilted 1 X 1 tilings).

%H R. H. Hardin, <a href="/A235241/b235241.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) + 39*a(n-2) - 152*a(n-3) - 441*a(n-4) + 1612*a(n-5) + 1185*a(n-6) - 3128*a(n-7) - 782*a(n-8).

%F Empirical g.f.: 2*x*(105 + 33*x - 4034*x^2 - 1124*x^3 + 43251*x^4 + 10791*x^5 - 84602*x^6 - 20036*x^7) / ((1 - 4*x - x^2)*(1 - 17*x^2)*(1 - 21*x^2 + 46*x^4)). - _Colin Barker_, Oct 17 2018

%e Some solutions for n=4:

%e ..4..1....0..1....3..7....5..7....4..6....6..2....5..6....4..7....4..2....4..2

%e ..1..4....5..0....6..4....7..3....5..1....1..3....7..2....5..2....3..7....3..7

%e ..3..0....6..7....3..7....4..6....2..4....4..0....5..6....2..5....2..0....7..5

%e ..1..4....7..2....2..0....5..1....6..2....2..4....7..2....4..1....3..7....2..6

%e ..3..0....6..7....1..5....0..2....1..3....4..0....0..1....2..5....4..2....4..2

%Y Column 1 of A235248.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 05 2014

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Last modified October 20 00:57 EDT 2021. Contains 348099 sequences. (Running on oeis4.)