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Number of (n+2)X(2+2) 0..2 arrays with no increasing sequence of length 3 horizontally or antidiagonally downwards
1

%I #4 Dec 11 2013 10:38:47

%S 388908,26851581,1853443458,127934319483,8830686982464,

%T 609539583118581,42073567268258250,2904134713566546240,

%U 200458363340939984253,13836670608153772979775,955078402954534730110719

%N Number of (n+2)X(2+2) 0..2 arrays with no increasing sequence of length 3 horizontally or antidiagonally downwards

%C Column 2 of A233497

%H R. H. Hardin, <a href="/A233491/b233491.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 69*a(n-1) +18*a(n-2) -1125*a(n-3) +108*a(n-4) +4131*a(n-5) -3402*a(n-6) +729*a(n-7)

%e Some solutions for n=1

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 11 2013