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A208704 Number of nX3 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors. 2

%I #26 Apr 06 2016 12:51:09

%S 4,28,196,1372,9604,67228,470596,3294172,23059204,161414428,

%T 1129900996,7909306972,55365148804,387556041628,2712892291396,

%U 18990246039772,132931722278404,930522055948828,6513654391641796,45595580741492572

%N Number of nX3 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.

%C Column 3 of A208709.

%H R. H. Hardin, <a href="/A208704/b208704.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 7*a(n-1).

%F Empirical: a(n) = (A198480(n)+1)*2 = (A024075(n)+1)*4. [_Martin Ettl_, Nov 09 2012; revised Nov 13 2012]

%e Some solutions for n=4

%e ..0..0..0....0..1..1....0..0..1....0..1..1....0..1..1....0..1..1....0..0..1

%e ..1..0..1....1..0..1....0..0..1....0..1..1....1..0..0....1..0..1....0..1..1

%e ..1..0..1....0..1..0....0..0..1....0..1..1....1..1..1....1..1..1....0..0..0

%e ..1..0..1....0..1..0....1..1..1....0..1..1....1..0..1....1..0..1....0..1..0

%Y Cf. A270471.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 01 2012

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Last modified March 29 05:43 EDT 2024. Contains 371264 sequences. (Running on oeis4.)