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Number of nXnXn triangular 0..1 arrays with new values introduced in sequential zero-upwards order and exactly one 2x2x2 triangle having values all equal.
2

%I #5 Mar 29 2016 21:10:48

%S 0,1,13,138,1628,23527,435147,10546164,339692832,14675385285,

%T 855707505235,67645098281722,7273718690098068,1066532362363098251,

%U 213665221064800026604,58573977551568152227368

%N Number of nXnXn triangular 0..1 arrays with new values introduced in sequential zero-upwards order and exactly one 2x2x2 triangle having values all equal.

%C Column 1 of A271075.

%H R. H. Hardin, <a href="/A271069/b271069.txt">Table of n, a(n) for n = 1..20</a>

%e Some solutions for n=4

%e .....0........0........0........0........0........0........0........0

%e ....0.1......0.0......1.0......0.1......1.0......1.0......1.0......1.1

%e ...1.1.1....0.1.1....1.0.0....1.1.1....1.0.0....1.0.1....0.0.0....0.1.0

%e ..1.0.0.1..0.1.0.0..0.1.1.0..1.0.0.0..0.0.1.1..0.0.0.1..1.1.1.1..1.0.1.0

%Y Cf. A271075.

%K nonn

%O 1,3

%A _R. H. Hardin_, Mar 29 2016