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%I #6 Oct 13 2021 14:58:37
%S 4,200,17336,1664244,161114424,15316983096,1419691311304,
%T 128192490487336,11293174782625768,972723674586291992,
%U 82102763053800998896,6805147718234252844940,554951326868228481044896
%N Number of side-n hexagonal 0..3 arrays with values nondecreasing E, SW and SE.
%C Column 3 of A216937.
%H R. H. Hardin, <a href="/A216932/b216932.txt">Table of n, a(n) for n = 1..21</a>
%e Some solutions for n=3
%e ......0.0.0..........0.0.1..........0.0.1..........0.1.1..........0.0.0
%e .....0.0.0.1........0.0.1.1........0.0.1.2........0.1.1.1........0.1.1.3
%e ....0.1.1.1.1......1.1.1.3.3......0.0.1.2.3......1.1.1.1.3......0.1.1.3.3
%e .....1.2.2.3........2.2.3.3........2.2.3.3........1.2.2.3........1.2.3.3
%e ......2.3.3..........2.3.3..........3.3.3..........3.3.3..........3.3.3
%Y Cf. A216937.
%K nonn
%O 1,1
%A _R. H. Hardin_ Sep 20 2012