%I #6 Apr 17 2022 20:54:19
%S 1,4,29,313,6150,145563,5219070,208181894,11412814314,670592486703,
%T 51088102234508,4085932956830052,407520605922011467,
%U 42123055901071684382,5279748839226156263229,679936583636831702045901
%N Number of horizontal, vertical and diagonal neighbor colorings of the even squares of an n X 4 array with new integer colors introduced in row major order.
%C Column 4 of A215959.
%H R. H. Hardin, <a href="/A215955/b215955.txt">Table of n, a(n) for n = 1..20</a>
%e Some solutions for n=4
%e ..0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x
%e ..x..2..x..3....x..1..x..0....x..1..x..2....x..2..x..3....x..2..x..3
%e ..4..x..0..x....2..x..3..x....3..x..4..x....2..x..4..x....2..x..0..x
%e ..x..1..x..2....x..4..x..2....x..5..x..1....x..3..x..5....x..0..x..2
%Y Cf. A215959.
%K nonn
%O 1,2
%A _R. H. Hardin_, Aug 28 2012