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Half the number of (n+1)X3 0..3 arrays with every 2X2 subblock having at most one duplicate clockwise edge difference
1

%I #5 Mar 31 2012 12:37:32

%S 1578,78628,3913002,194768054,9694276684,482519042626,24016699289368,

%T 1195397128587610,59499195398348818,2961488004421137772,

%U 147403862192382974048,7336818031079109775274,365179704387717596682932

%N Half the number of (n+1)X3 0..3 arrays with every 2X2 subblock having at most one duplicate clockwise edge difference

%C Column 2 of A210300

%H R. H. Hardin, <a href="/A210294/b210294.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 44*a(n-1) +330*a(n-2) -1940*a(n-3) -9738*a(n-4) +33341*a(n-5) +57999*a(n-6) -257279*a(n-7) +188734*a(n-8) +117676*a(n-9) -161670*a(n-10) +4796*a(n-11) +34416*a(n-12) -4912*a(n-13) -1536*a(n-14)

%e Some solutions for n=4

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 19 2012