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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 #11 Jun 19 2022 00:04:31

%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 September 21 08:32 EDT 2023. Contains 365499 sequences. (Running on oeis4.)