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A198522 Number of n X 2 0..4 arrays with values 0..4 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors.

%I A198522 #8 Apr 21 2021 11:02:13
%S A198522 2,15,193,3660,81844,1948672,47436498,1163606279,28617909415,
%T A198522 704465305625,17346617064022,427184684002131,10520398796919219,
%U A198522 259092051772297458,6380839372392481249,157145577058895542027
%N A198522 Number of n X 2 0..4 arrays with values 0..4 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors.
%C A198522 Column 2 of A198528.
%H A198522 R. H. Hardin, <a href="/A198522/b198522.txt">Table of n, a(n) for n = 1..200</a>
%F A198522 Empirical: a(n) = 35*a(n-1) -267*a(n-2) +246*a(n-3) +924*a(n-4) +710*a(n-5) -1736*a(n-6) -1860*a(n-7) +72*a(n-8) +1984*a(n-9) +720*a(n-10) -320*a(n-11) -512*a(n-12) for n > 14.
%e A198522 Some solutions for n=4
%e A198522 ..0..0....0..1....0..0....0..1....0..1....0..1....0..1....0..0....0..1....0..0
%e A198522 ..0..1....2..0....1..0....2..3....2..0....2..0....0..2....0..1....2..3....1..2
%e A198522 ..2..3....2..2....2..3....4..2....1..0....0..2....1..3....1..0....1..2....1..3
%e A198522 ..2..2....3..1....0..1....0..3....2..1....2..3....0..0....0..0....1..0....1..2
%Y A198522 Cf. A198528.
%K A198522 nonn
%O A198522 1,1
%A A198522 _R. H. Hardin_ Oct 26 2011