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%I #6 Nov 30 2021 18:31:56
%S 4,53,811,12270,184193,2764070,41480899,622510123,9342086217,
%T 140197824897,2103965848896,31574471975014,473841949757344,
%U 7111003899609738,106715702327136893,1601495553082204043
%N Number of n X 4 arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, without move-in move-out left turns.
%C Column 4 of A221609.
%e Some solutions for n=3
%e ..1..2..1..0....0..2..2..1....1..1..0..2....0..2..2..1....0..3..2..0
%e ..1..2..0..1....1..2..1..0....0..2..3..0....1..0..0..0....0..0..2..1
%e ..1..1..2..0....1..1..1..0....1..0..1..1....1..3..2..0....0..2..2..0
%Y Cf. A221609.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 20 2013
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