A232251 - OEIS

%I #7 Oct 03 2018 13:57:45

%S 37,421,4711,52779,591181,6622029,74175439,830862931,9306762101,

%T 104248027381,1167715590199,13079956849787,146512791834269,

%U 1641136772671133,18382899355702175,205912751666562211

%N Number of (n+1) X (2+1) 0..2 arrays with every element both >= and <= some horizontal or antidiagonal neighbor.

%H R. H. Hardin, <a href="/A232251/b232251.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 10*a(n-1) + 14*a(n-2) - 6*a(n-3) - a(n-4).

%F Empirical g.f.: x*(37 + 51*x - 17*x^2 - 3*x^3) / (1 - 10*x - 14*x^2 + 6*x^3 + x^4). - _Colin Barker_, Oct 03 2018

%e Some solutions for n=4:

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

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

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

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

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

%Y Column 2 of A232257.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 21 2013