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Number of 4Xn arrays containing n copies of 0..4-1 with every element equal to or 1 greater than any north or west neighbors modulo 4 and the upper left element equal to 0.
1

%I #6 Aug 12 2016 06:54:16

%S 1,2,5,25,182,1256,7396,39891,210384,1168317,7080023,45942141,

%T 304138329,1984289501,12627984625,79001714951,493690545161,

%U 3127108593615,20194195021000,132397182653318,873218912983165,5749093679423621

%N Number of 4Xn arrays containing n copies of 0..4-1 with every element equal to or 1 greater than any north or west neighbors modulo 4 and the upper left element equal to 0.

%C Row 4 of A268115.

%H R. H. Hardin, <a href="/A268120/b268120.txt">Table of n, a(n) for n = 1..34</a>

%e Some solutions for n=6

%e ..0..0..1..2..3..3....0..1..2..3..3..0....0..0..1..1..2..3....0..0..1..2..3..3

%e ..1..1..2..2..3..0....0..1..2..3..3..0....0..1..1..2..3..3....1..1..2..3..3..0

%e ..1..2..3..3..0..0....1..1..2..3..0..1....1..2..2..3..0..0....1..2..2..3..0..0

%e ..2..2..3..0..1..1....2..2..2..3..0..1....2..2..3..3..0..1....2..2..3..0..1..1

%Y Cf. A268115.

%K nonn

%O 1,2

%A _R. H. Hardin_, Jan 26 2016