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Number of 4Xn arrays containing n copies of 0..4-1 with no element 1 greater than its north, southwest or northwest neighbor modulo 4 and the upper left element equal to 0.
1

%I #6 Aug 12 2016 06:53:59

%S 2,7,76,943,12549,205452,3751651,72345624,1439333469,29337850346,

%T 606171318095,12663996785919,266620124227464,5654752201437201,

%U 120600246762266928,2585771905289878628,55681094061639376374

%N Number of 4Xn arrays containing n copies of 0..4-1 with no element 1 greater than its north, southwest or northwest neighbor modulo 4 and the upper left element equal to 0.

%C Row 4 of A266878.

%H R. H. Hardin, <a href="/A266880/b266880.txt">Table of n, a(n) for n = 1..20</a>

%e Some solutions for n=4

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

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

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

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

%Y Cf. A266878.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 05 2016