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A203177 Number of nX4 0..2 arrays with every 1 immediately preceded by 0 to the left or above, no 0 immediately preceded by a 0, and every 2 immediately preceded by 0 1 to the left or above.

%I A203177 #7 Jul 22 2025 17:02:41
%S A203177 2,4,17,59,205,724,2466,8948,30945,108083,382615,1333850,4692643,
%T A203177 16441939,57654309,202490869,709321155,2489832932,8732839148,
%U A203177 30624223891,107449317301,376820699674,1321873641658,4636665217896,16263018992261
%N A203177 Number of nX4 0..2 arrays with every 1 immediately preceded by 0 to the left or above, no 0 immediately preceded by a 0, and every 2 immediately preceded by 0 1 to the left or above.
%C A203177 Column 4 of A203181
%H A203177 R. H. Hardin, <a href="/A203177/b203177.txt">Table of n, a(n) for n = 1..210</a>
%F A203177 Empirical: a(n) = 5*a(n-2) +34*a(n-3) +13*a(n-4) -38*a(n-5) -419*a(n-6) -124*a(n-7) +145*a(n-8) +2520*a(n-9) +37*a(n-10) -584*a(n-11) -6715*a(n-12) +1170*a(n-13) +55*a(n-14) +6304*a(n-15) +476*a(n-16) -78*a(n-17) -480*a(n-19)
%e A203177 Some solutions for n=5
%e A203177 ..0..1..2..0....0..1..2..0....0..1..2..0....0..1..2..0....0..1..0..1
%e A203177 ..1..0..1..1....1..0..1..1....1..0..1..2....1..0..1..1....1..0..1..0
%e A203177 ..0..1..0..1....0..1..2..0....0..1..2..0....0..1..0..1....0..1..0..1
%e A203177 ..1..2..1..0....1..2..0..1....1..0..1..1....1..2..1..0....1..0..1..0
%e A203177 ..0..1..0..1....0..1..1..2....0..1..2..0....2..0..2..1....2..1..2..1
%K A203177 nonn
%O A203177 1,1
%A A203177 _R. H. Hardin_ Dec 30 2011