A205209 - OEIS

%I #5 Mar 31 2012 12:37:05

%S 452,3248,23578,203313,1846145,17014174,157776973,1467364433,

%T 13666197180,127366953026,1187443362372,11072379506700,

%U 103253395267594,962908489874374,8979955402839772,83746661590075524,781021282761628826

%N Number of (n+1)X3 0..2 arrays with the determinants of 2X2 subblocks nondecreasing rightwards and downwards

%C Column 2 of A205215

%H R. H. Hardin, <a href="/A205209/b205209.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 15*a(n-1) -49*a(n-2) -97*a(n-3) +664*a(n-4) -980*a(n-5) +448*a(n-6) for n>13

%e Some solutions for n=4

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Jan 23 2012