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 A232591 Number of (2+1) X (n+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally or antidiagonally, with no adjacent elements equal. 1

%I #7 Oct 05 2018 12:00:18

%S 2,34,12,152,108,690,744,3232,4516,15592,25724,76914,141516,385622,

%T 762648,1955944,4058152,10001440,21421592,51425362,112496648,

%U 265415854,588810972,1373336224,3075128652,7118096080,16037159652,36935382354

%N Number of (2+1) X (n+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally or antidiagonally, with no adjacent elements equal.

%H R. H. Hardin, <a href="/A232591/b232591.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 5*a(n-2) + 4*a(n-3) - 3*a(n-4) - 12*a(n-5) - 3*a(n-6) + 6*a(n-7) + 6*a(n-8) + 2*a(n-9) for n>10.

%F Empirical g.f.: x*(1 + 17*x + x^2 - 13*x^3 - 41*x^4 + 4*x^5 + 23*x^6 + 20*x^7 + 2*x^8 - x^9) / (1 - 5*x^2 - 4*x^3 + 3*x^4 + 12*x^5 + 3*x^6 - 6*x^7 - 6*x^8 - 2*x^9). - _Colin Barker_, Oct 05 2018

%e Some solutions for n=7:

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

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

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

%Y Row 2 of A232589.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 26 2013

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Last modified May 18 19:36 EDT 2024. Contains 372666 sequences. (Running on oeis4.)