A224369 - OEIS

%I #8 Aug 30 2018 06:07:18

%S 22,218,1838,15540,132236,1126072,9588028,81634704,695055928,

%T 5917866680,50386093544,428998916880,3652596505952,31099055733376,

%U 264784589835472,2254437550085472,19194805371407680,163429034985577568

%N Number of n X 3 0..2 arrays with rows unimodal and antidiagonals nondecreasing.

%C Column 3 of A224374.

%H R. H. Hardin, <a href="/A224369/b224369.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 10*a(n-1) - 16*a(n-2) + 30*a(n-3) - 14*a(n-4) + 12*a(n-5).

%F Empirical g.f.: 2*x*(1 + x + x^2)*(11 - 12*x + 6*x^2) / (1 - 10*x + 16*x^2 - 30*x^3 + 14*x^4 - 12*x^5). - _Colin Barker_, Aug 30 2018

%e Some solutions for n=3:

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

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

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

%Y Cf. A224374.

%K nonn

%O 1,1

%A _R. H. Hardin_, Apr 05 2013