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Number of 5X5X5 triangular 0..n arrays with some element plus some adjacent element totalling n+1 or n-1 exactly once.
1

%I #4 Mar 20 2016 11:05:15

%S 0,0,443088,46957788,1008327378,25162747992,271906503420,

%T 2992465755612,20367499465482,129329174634672,624840436639956,

%U 2766099092355012,10373656913823810,35810603737855596,111074891756040534

%N Number of 5X5X5 triangular 0..n arrays with some element plus some adjacent element totalling n+1 or n-1 exactly once.

%C Row 5 of A270606.

%H R. H. Hardin, <a href="/A270610/b270610.txt">Table of n, a(n) for n = 1..25</a>

%e Some solutions for n=3

%e ......0..........0..........0..........0..........2..........0..........0

%e .....0.3........0.0........2.3........0.0........0.3........0.0........0.3

%e ....0.0.3......3.0.0......3.3.3......3.0.0......0.3.3......1.0.3......0.0.3

%e ...0.0.3.2....0.3.3.1....3.3.2.3....3.0.1.0....3.3.3.3....3.0.3.2....0.3.0.0

%e ..3.0.3.2.1..0.3.3.0.0..0.0.3.3.0..3.0.0.3.0..0.3.3.3.2..2.3.3.3.3..3.3.0.3.1

%Y Cf. A270606.

%K nonn

%O 1,3

%A _R. H. Hardin_, Mar 20 2016