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A205470 Number of (n+1)X4 0..2 arrays with every 2X2 subblock having the same number of equal edges, and new values 0..2 introduced in row major order.

%I A205470 #7 Jul 22 2025 18:54:45
%S A205470 175,1548,14639,147129,1504556,15614579,162976758,1709130780,
%T A205470 17963198743,189127385194,1993106187666,21019022873891,
%U A205470 221754001074914,2340228495931166,24701472352877203,260760556151955406
%N A205470 Number of (n+1)X4 0..2 arrays with every 2X2 subblock having the same number of equal edges, and new values 0..2 introduced in row major order.
%C A205470 Column 3 of A205475
%H A205470 R. H. Hardin, <a href="/A205470/b205470.txt">Table of n, a(n) for n = 1..210</a>
%F A205470 Empirical: a(n) = 20*a(n-1) -75*a(n-2) -688*a(n-3) +5022*a(n-4) -496*a(n-5) -63723*a(n-6) +111258*a(n-7) +251463*a(n-8) -817674*a(n-9) -9180*a(n-10) +2101200*a(n-11) -1759426*a(n-12) -1578136*a(n-13) +2839836*a(n-14) -596208*a(n-15) -1049272*a(n-16) +620728*a(n-17) +18624*a(n-18) -96072*a(n-19) +24528*a(n-20) -1728*a(n-21)
%e A205470 Some solutions for n=4
%e A205470 ..0..0..1..1....0..1..1..0....0..1..0..2....0..0..0..0....0..0..1..2
%e A205470 ..2..0..1..0....1..1..0..0....1..1..0..0....1..1..0..2....1..2..1..0
%e A205470 ..0..0..0..0....2..1..0..1....2..1..1..1....1..0..0..2....0..0..1..2
%e A205470 ..2..2..0..1....1..1..0..0....1..1..2..1....0..0..2..2....1..2..1..0
%e A205470 ..2..0..0..0....1..0..0..1....1..2..2..1....0..2..2..0....0..0..1..2
%K A205470 nonn
%O A205470 1,1
%A A205470 _R. H. Hardin_ Jan 27 2012