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A221930 Number of 2Xn arrays of occupancy after each element stays put or moves to some horizontal, diagonal or antidiagonal neighbor, without move-in move-out straight through or left turns.

%I A221930 #6 Jul 23 2025 02:20:28
%S A221930 1,25,232,2197,20933,198589,1885324,17896442,169874679,1612469540,
%T A221930 15305706000,145283086944,1379039583394,13089962041815,
%U A221930 124251041949203,1179401540313291,11194980504773785,106263714435179508
%N A221930 Number of 2Xn arrays of occupancy after each element stays put or moves to some horizontal, diagonal or antidiagonal neighbor, without move-in move-out straight through or left turns.
%C A221930 Row 2 of A221929
%H A221930 R. H. Hardin, <a href="/A221930/b221930.txt">Table of n, a(n) for n = 1..55</a>
%F A221930 Empirical: a(n) = 9*a(n-1) +10*a(n-2) -45*a(n-3) -57*a(n-4) +45*a(n-5) -3*a(n-6) -616*a(n-7) -57*a(n-8) +1200*a(n-9) -268*a(n-10) -289*a(n-11) -9*a(n-12) +6*a(n-13)
%e A221930 Some solutions for n=3
%e A221930 ..1..2..0....2..1..0....0..0..1....0..0..1....0..1..2....2..2..1....1..1..3
%e A221930 ..0..3..0....1..1..1....0..5..0....0..3..2....0..2..1....0..1..0....0..0..1
%K A221930 nonn
%O A221930 1,2
%A A221930 _R. H. Hardin_ Feb 01 2013