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A209587 Number of n X n 0..2 arrays with every element equal to a diagonal or antidiagonal reflection.

%I A209587 #8 Jul 22 2025 21:49:58
%S A209587 3,81,3645,1476225,996451875,6053445140625,61291132048828125,
%T A209587 5585154407949462890625,848245325707324676513671875,
%U A209587 1159445329576199417209625244140625
%N A209587 Number of n X n 0..2 arrays with every element equal to a diagonal or antidiagonal reflection.
%C A209587 Column 2 of A209593
%H A209587 R. H. Hardin, <a href="/A209587/b209587.txt">Table of n, a(n) for n = 1..30</a>
%F A209587 a(n) = 3 ^ (2*n-(n modulo 2)) * 15 ^ ((n*n-2*n+(n modulo 2))/4)
%e A209587 Some solutions for n=3
%e A209587 ..1..1..1....2..0..1....0..1..1....2..0..2....2..0..0....0..2..1....0..2..0
%e A209587 ..1..2..2....0..1..2....1..2..1....2..1..0....0..0..0....2..1..0....1..1..2
%e A209587 ..0..2..0....1..2..0....0..1..2....1..2..0....0..0..1....1..0..2....0..1..2
%K A209587 nonn
%O A209587 1,1
%A A209587 _R. H. Hardin_ Mar 10 2012