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 A231998 Number of (1+1) X (n+1) 0..1 arrays with no element having a strict majority of its horizontal and antidiagonal neighbors equal to one. 1

%I

%S 4,6,16,39,81,168,361,780,1681,3612,7744,16620,35721,76755,164836,

%T 354006,760384,1633275,3508129,7535088,16184529,34762680,74666881,

%U 160377096,344473600,739894200,1589218225,3413480691,7331811876,15747991350

%N Number of (1+1) X (n+1) 0..1 arrays with no element having a strict majority of its horizontal and antidiagonal neighbors equal to one.

%H R. H. Hardin, <a href="/A231998/b231998.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) + 3*a(n-3) + 3*a(n-4) + 3*a(n-5) + 3*a(n-6) - 2*a(n-8) - a(n-9).

%F Empirical g.f.: x*(4 + 2*x + 10*x^2 + 11*x^3 + 12*x^4 + 9*x^5 - 2*x^6 - 7*x^7 - 3*x^8) / ((1 + x^2 - x^3)*(1 + x^2 + x^3)*(1 - x - 2*x^2 - x^3)). - _Colin Barker_, Oct 01 2018

%e Some solutions for n=7:

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

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

%Y Row 1 of A231997.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 16 2013

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Last modified May 28 13:05 EDT 2022. Contains 354115 sequences. (Running on oeis4.)