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A229443 Number of nX6 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, and rows and columns lexicographically nondecreasing.

%I A229443 #6 Jul 23 2025 05:45:20
%S A229443 8,25,93,387,1609,6374,23610,81177,258698,765702,2113491,5467941,
%T A229443 13331626,30795942,67738085,142526854,288060848,561310955,1057997269,
%U A229443 1934623043,3440842683,5966088386,10105555904,16752093179,27222289586
%N A229443 Number of nX6 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, and rows and columns lexicographically nondecreasing.
%C A229443 Column 6 of A229445
%H A229443 R. H. Hardin, <a href="/A229443/b229443.txt">Table of n, a(n) for n = 1..210</a>
%F A229443 Empirical: a(n) = (73/159667200)*n^12 - (19/26611200)*n^11 + (19/2903040)*n^10 + (47/161280)*n^9 - (1259/1612800)*n^8 + (7711/806400)*n^7 - (10715/580608)*n^6 + (30575/96768)*n^5 - (4597853/3628800)*n^4 + (1198483/201600)*n^3 - (621689/55440)*n^2 + (168439/9240)*n - 4
%e A229443 Some solutions for n=4
%e A229443 ..0..0..0..2..2..2....0..0..2..2..2..2....0..0..0..2..2..2....0..0..2..2..2..2
%e A229443 ..1..1..1..0..0..2....0..0..2..2..2..2....1..1..1..0..2..2....1..1..0..0..0..2
%e A229443 ..1..1..1..1..1..0....1..1..0..2..2..2....1..1..1..1..0..2....2..2..1..1..1..0
%e A229443 ..2..2..2..1..1..1....1..1..1..0..2..2....2..2..2..2..1..0....2..2..2..2..2..1
%K A229443 nonn
%O A229443 1,1
%A A229443 _R. H. Hardin_ Sep 23 2013