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 A228799 Number of 4 X n binary arrays with top left element equal to 1 and no two ones adjacent horizontally or nw-se. 1

%I #12 Sep 13 2018 09:31:51

%S 8,13,156,586,3957,19474,111966,596273,3292024,17872116,97776195,

%T 533053286,2910670434,15882108643,86688323910,473098799920,

%U 2582083666591,14092131350712,76910993201528,419756836650551,2290910858988482

%N Number of 4 X n binary arrays with top left element equal to 1 and no two ones adjacent horizontally or nw-se.

%H R. H. Hardin, <a href="/A228799/b228799.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) + 20*a(n-2) + 27*a(n-3) - 14*a(n-4) - 25*a(n-5) + 4*a(n-6) + 5*a(n-7) - a(n-8).

%F Empirical g.f.: x*(8 + 5*x - 17*x^2 - 46*x^3 + 12*x^4 - 33*x^5 + 7*x^6) / ((1 + x)*(1 + 2*x - x^2)*(1 - 4*x - 9*x^2 + 5*x^3 + 4*x^4 - x^5)). - _Colin Barker_, Sep 13 2018

%e Some solutions for n=4:

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

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

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

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

%Y Row 4 of A228796.

%K nonn

%O 1,1

%A _R. H. Hardin_, Sep 04 2013

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Last modified May 29 22:39 EDT 2023. Contains 363044 sequences. (Running on oeis4.)