A232131 - OEIS

%I #7 Oct 03 2018 08:41:36

%S 36,728,14752,298912,6056640,122721280,2486611712,50384397824,

%T 1020902270976,20685797427200,419141212008448,8492752393142272,

%U 172082441775661056,3486780892303556608,70650095765044723712

%N Number of (n+1) X (2+1) 0..2 arrays with no element equal to a strict majority of its horizontal and antidiagonal neighbors, with values 0..2 introduced in row major order.

%H R. H. Hardin, <a href="/A232131/b232131.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 22*a(n-1) - 36*a(n-2) + 16*a(n-3).

%F Empirical g.f.: 4*x*(9 - 16*x + 8*x^2) / (1 - 22*x + 36*x^2 - 16*x^3). - _Colin Barker_, Oct 03 2018

%e Some solutions for n=4:

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

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

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

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

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

%Y Column 2 of A232137.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 19 2013