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A203970 Number of nX3 0..2 arrays with every 1 immediately preceded by 0 to the left or above, and every 2 immediately preceded by 0 1 to the left or above.

%I A203970 #7 Jul 22 2025 17:41:40
%S A203970 4,29,258,2061,16723,136243,1107082,9001543,73188575,595039791,
%T A203970 4837958263,39334611930,319806460796,2600161056897,21140392838611,
%U A203970 171880201142842,1397457732946504,11361914049797193,92377098701406680
%N A203970 Number of nX3 0..2 arrays with every 1 immediately preceded by 0 to the left or above, and every 2 immediately preceded by 0 1 to the left or above.
%C A203970 Column 3 of A203975
%H A203970 R. H. Hardin, <a href="/A203970/b203970.txt">Table of n, a(n) for n = 1..210</a>
%F A203970 Empirical: a(n) = 4*a(n-1) +14*a(n-2) +134*a(n-3) +164*a(n-4) +465*a(n-5) -951*a(n-6) -633*a(n-7) -3451*a(n-8) +4286*a(n-9) +1728*a(n-10) +5640*a(n-11) -7916*a(n-12) -1912*a(n-13) -2947*a(n-14) +6073*a(n-15) +752*a(n-16) +143*a(n-17) -1899*a(n-18) +55*a(n-19) +89*a(n-20) +178*a(n-21) -5*a(n-22) -5*a(n-23) -5*a(n-24)
%e A203970 Some solutions for n=5
%e A203970 ..0..0..1....0..0..1....0..0..0....0..0..0....0..0..0....0..1..2....0..0..0
%e A203970 ..0..0..0....1..0..0....1..1..1....0..1..2....1..0..1....0..0..1....0..1..1
%e A203970 ..0..1..1....0..1..0....0..0..2....1..0..0....0..0..1....0..0..0....0..0..2
%e A203970 ..1..2..0....1..0..0....1..1..0....0..1..1....0..0..1....0..0..0....0..0..0
%e A203970 ..0..0..0....2..1..1....2..2..1....0..1..0....0..1..2....1..1..0....0..1..0
%K A203970 nonn
%O A203970 1,1
%A A203970 _R. H. Hardin_ Jan 08 2012