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

%I #6 Sep 25 2021 10:15:45

%S 7959956,1231134446,192011782168,29957246808751,4668375990645847,

%T 727613390704042525,113382378138032185191,17668628991719709583658,

%U 2753265874450249736710283,429037614663717954349428385

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

%C Row 2 of A233801.

%H R. H. Hardin, <a href="/A233803/b233803.txt">Table of n, a(n) for n = 1..210</a>

%e Some solutions for n=1

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

%e ..1..2..1....1..1..3....1..0..0....0..3..0....0..2..1....0..1..0....0..2..1

%e ..1..2..1....1..0..2....0..0..3....3..0..1....2..2..3....0..0..0....0..0..1

%e ..2..2..2....1..2..1....0..3..0....0..2..0....2..2..0....2..1..3....2..3..3

%Y Cf. A233801.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 16 2013