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A235232 Number of (n+1) X (1+1) 0..6 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 120,420,1328,4652,14944,52468,170864,601100,1980544,6979348,23223440,

%T 81953324,274931488,971325748,3280518320,11600884556,39397352128,

%U 139427487316,475663660496,1684432450412,5768254899040,20437259824756

%N Number of (n+1) X (1+1) 0..6 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="/A235232/b235232.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) + 23*a(n-2) - 63*a(n-3) - 153*a(n-4) + 333*a(n-5) + 249*a(n-6) - 81*a(n-7) - 54*a(n-8).

%F Empirical g.f.: 4*x*(30 + 15*x - 673*x^2 - 358*x^3 + 3816*x^4 + 2151*x^5 - 933*x^6 - 528*x^7) / ((1 - 3*x)*(1 + 3*x)*(1 - 3*x - 2*x^2)*(1 - 12*x^2 + 3*x^4)). - _Colin Barker_, Oct 17 2018

%e Some solutions for n=4:

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

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

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

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

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

%Y Column 1 of A235239.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 05 2014

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Last modified July 23 12:19 EDT 2021. Contains 346259 sequences. (Running on oeis4.)