The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #8 Oct 03 2025 17:07:02
%S 1,1,4,8,102,364,8460,40612,1440676,8520924,419195864,2916070032,
%T 187464151920,1489852279864,120167989574768,1069484429786480,
%U 105066789765860688,1031932540617115200,120715131903960979168
%N Number of horizontal, vertical, diagonal and antidiagonal neighbor colorings of the even squares of an nX3 array with new integer colors introduced in row major order.
%C Column 3 of A215847
%H R. H. Hardin, <a href="/A215844/b215844.txt">Table of n, a(n) for n = 1..42</a>
%e Some solutions for n=4
%e ..0..x..1....0..x..1....0..x..1....0..x..1....0..x..1....0..x..1....0..x..1
%e ..x..2..x....x..2..x....x..2..x....x..2..x....x..2..x....x..2..x....x..2..x
%e ..3..x..0....3..x..4....1..x..3....3..x..4....3..x..0....3..x..4....1..x..0
%e ..x..1..x....x..1..x....x..4..x....x..5..x....x..4..x....x..0..x....x..3..x
%K nonn
%O 1,3
%A _R. H. Hardin_, Aug 24 2012