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A208496 Number of n X 3 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 0 and 1 1 1 vertically. 2

%I #10 Mar 06 2018 14:58:49

%S 6,36,60,126,234,456,896,1722,3360,6512,12642,24570,47644,92568,

%T 179690,348800,677340,1314846,2552850,4956336,9622272,18681842,

%U 36269696,70416640,136712226,265421170,515308500,1000454184,1942349698,3771013664

%N Number of n X 3 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 0 and 1 1 1 vertically.

%C Column 3 of A208501.

%H R. H. Hardin, <a href="/A208496/b208496.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-2) + 4*a(n-3) + 2*a(n-4) + 2*a(n-5) - 2*a(n-6) + a(n-7) + a(n-9) for n>11.

%F Empirical g.f.: 2*x*(3 + 18*x + 27*x^2 + 33*x^3 + 9*x^4 + 3*x^5 - 11*x^6 + 12*x^7 + 2*x^8 + 6*x^9 - 2*x^10) / (1 - x^2 - 4*x^3 - 2*x^4 - 2*x^5 + 2*x^6 - x^7 - x^9). - _Colin Barker_, Mar 06 2018

%e Some solutions for n=4:

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

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

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

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

%Y Cf. A208501.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 27 2012

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Last modified May 20 12:18 EDT 2024. Contains 372712 sequences. (Running on oeis4.)