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A204074 Number of (n+1)X7 0..2 arrays with every 2X2 subblock having equal diagonal elements or equal antidiagonal elements, and new values 0..2 introduced in row major order.

%I A204074 #7 Jul 22 2025 17:45:20
%S A204074 23438,1944977,173848010,15960507749,1480470688070,137884925726873,
%T A204074 12862680257580962,1200667125506097389,112104534764514944606,
%U A204074 10468081339649563612769,977525613860679565008506
%N A204074 Number of (n+1)X7 0..2 arrays with every 2X2 subblock having equal diagonal elements or equal antidiagonal elements, and new values 0..2 introduced in row major order.
%C A204074 Column 6 of A204076
%H A204074 R. H. Hardin, <a href="/A204074/b204074.txt">Table of n, a(n) for n = 1..210</a>
%F A204074 Empirical: a(n) = 118*a(n-1) -731*a(n-2) -192994*a(n-3) +4365504*a(n-4) +7243432*a(n-5) -853595552*a(n-6) +4227025728*a(n-7) +47143688896*a(n-8) -407296962944*a(n-9) -429798333440*a(n-10) +11467618407936*a(n-11) -17466577684480*a(n-12) -111724579282944*a(n-13) +316040356208640*a(n-14) +361767531462656*a(n-15) -1868808138063872*a(n-16) +221838313259008*a(n-17) +4652179449380864*a(n-18) -2844522127687680*a(n-19) -5181635339747328*a(n-20) +4553597538271232*a(n-21) +2457666202894336*a(n-22) -2755619987652608*a(n-23) -413275992883200*a(n-24) +684703879266304*a(n-25) -18283340234752*a(n-26) -55383771054080*a(n-27) +8506451165184*a(n-28) -260919263232*a(n-29)
%e A204074 Some solutions for n=4
%e A204074 ..0..1..2..0..2..2..0....0..0..0..1..2..0..1....0..0..0..1..2..1..2
%e A204074 ..1..1..1..2..1..2..2....2..0..2..0..1..2..0....0..0..1..0..1..0..1
%e A204074 ..1..0..1..1..1..1..2....0..1..0..1..2..1..2....2..0..0..0..0..2..0
%e A204074 ..0..2..0..1..2..1..1....1..0..2..0..1..1..1....1..2..0..0..1..0..2
%e A204074 ..0..0..2..0..1..2..1....1..1..0..1..1..1..0....2..1..2..0..0..2..2
%K A204074 nonn
%O A204074 1,1
%A A204074 _R. H. Hardin_ Jan 10 2012