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A216461 Number of horizontal, diagonal and antidiagonal neighbor colorings of the even squares of a 3Xn array with new integer colors introduced in row major order.

%I A216461 #6 Jul 22 2025 23:32:17
%S A216461 2,2,7,15,203,716,17733,83440,3137543,18171918,942426468,6423127757,
%T A216461 433245459699,3376465219485,284615058572536,2486327138729353,
%U A216461 254421641605158901,2454996141671330713,298288744434946125073
%N A216461 Number of horizontal, diagonal and antidiagonal neighbor colorings of the even squares of a 3Xn array with new integer colors introduced in row major order.
%C A216461 Row 3 of A216460
%H A216461 R. H. Hardin, <a href="/A216461/b216461.txt">Table of n, a(n) for n = 1..41</a>
%e A216461 Some solutions for n=4
%e A216461 ..0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x
%e A216461 ..x..2..x..0....x..2..x..3....x..2..x..3....x..2..x..3....x..2..x..0
%e A216461 ..0..x..3..x....3..x..4..x....4..x..5..x....0..x..1..x....3..x..4..x
%K A216461 nonn
%O A216461 1,1
%A A216461 _R. H. Hardin_ Sep 07 2012