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A183331 Number of n X 3 binary arrays with each 1 adjacent to exactly two 0's. 1

%I #10 Apr 05 2020 21:41:21

%S 2,10,26,66,194,534,1468,4102,11402,31644,87958,244418,679050,1886836,

%T 5242786,14567272,40476178,112465998,312494040,868285644,2412590548,

%U 6703544510,18626248566,51754284540,143802757136,399565623778

%N Number of n X 3 binary arrays with each 1 adjacent to exactly two 0's.

%C Column 3 of A183335.

%H R. H. Hardin, <a href="/A183331/b183331.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 2*a(n-1) + a(n-2) + 3*a(n-3) + a(n-5) + 3*a(n-6) - a(n-7) - 3*a(n-8) - a(n-9).

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

%e Some solutions for 4 X 3:

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

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

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

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

%Y Cf. A183335.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 03 2011

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Last modified July 18 18:59 EDT 2024. Contains 374388 sequences. (Running on oeis4.)