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%I #8 Aug 24 2018 08:52:15
%S 4,16,54,177,596,2024,6869,23285,78942,267681,907708,3078001,10437337,
%T 35392507,120014445,406963770,1379996360,4679507294,15868004855,
%U 53807711762,182459601684,618712543947,2098027226581,7114318736716
%N Number of n X 3 0..1 arrays with diagonals and antidiagonals unimodal and rows nondecreasing.
%C Column 3 of A223949.
%H R. H. Hardin, <a href="/A223944/b223944.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 4*a(n-1) - 2*a(n-2) - a(n-3) + 5*a(n-4) - 8*a(n-5).
%F Empirical g.f.: x*(4 - 2*x^2 - 3*x^3 - 8*x^4) / (1 - 4*x + 2*x^2 + x^3 - 5*x^4 + 8*x^5). - _Colin Barker_, Aug 24 2018
%e Some solutions for n=3:
%e ..0..1..1....0..0..0....1..1..1....0..0..0....0..1..1....0..0..0....1..1..1
%e ..0..0..1....0..0..1....1..1..1....0..0..1....1..1..1....1..1..1....0..0..0
%e ..0..1..1....1..1..1....0..0..1....0..0..1....1..1..1....0..0..0....0..0..0
%Y Cf. A223949.
%K nonn
%O 1,1
%A _R. H. Hardin_, Mar 29 2013
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