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 A204794 Number of (n+1) X 3 0..1 arrays with rows and columns of determinants of all 2 X 2 subblocks lexicographically nondecreasing. 1

%I #10 Jun 10 2018 20:47:38

%S 47,240,1001,4273,18550,81009,353975,1547377,6764879,29576797,

%T 129315563,565399369,2472075383,10808590261,47258158979,206625890401,

%U 903426368975,3950033937229,17270659001435,75512178579577,330160485651239

%N Number of (n+1) X 3 0..1 arrays with rows and columns of determinants of all 2 X 2 subblocks lexicographically nondecreasing.

%C Column 2 of A204800.

%H R. H. Hardin, <a href="/A204794/b204794.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) - 5*a(n-2) - 12*a(n-3) + 12*a(n-4) for n > 8.

%F Empirical g.f.: x*(47 - 42*x - 204*x^2 + 31*x^3 + 233*x^4 + 206*x^5 - 65*x^6 - 104*x^7) / ((1 - x)*(1 - 2*x)*(1 - 3*x - 6*x^2)). - _Colin Barker_, Jun 10 2018

%e Some solutions for n=4:

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

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

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

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

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

%Y Cf. A204800.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 19 2012

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Last modified March 3 16:49 EST 2024. Contains 370512 sequences. (Running on oeis4.)