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 A221122 Number of n X 4 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor. 1

%I #10 Aug 03 2018 21:08:21

%S 21,1950,179300,16436223,1506094707,138001217828,12644783009532,

%T 1158616222843158,106161685080363377,9727382617196220288,

%U 891300589691816054472,81668088157651470747218,7483083373227566657384892

%N Number of n X 4 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor.

%C Column 4 of A221125.

%H R. H. Hardin, <a href="/A221122/b221122.txt">Table of n, a(n) for n = 1..18</a>

%F Empirical: a(n) = 109*a(n-1) - 1680*a(n-2) + 8230*a(n-3) - 13300*a(n-4) + 2025*a(n-5) for n>6.

%F Empirical g.f.: x*(21 - 339*x + 2030*x^2 - 4307*x^3 + 1200*x^4 + 2880*x^5) / (1 - 109*x + 1680*x^2 - 8230*x^3 + 13300*x^4 - 2025*x^5). - _Colin Barker_, Aug 03 2018

%e Some solutions for n=3:

%e 1 1 1 0 0 3 1 1 0 2 0 2 1 1 0 1 1 0 2 0

%e 1 2 1 1 1 1 1 2 1 3 0 1 0 1 3 0 0 3 4 0

%e 0 1 3 0 0 1 0 1 0 0 1 2 0 3 1 1 0 1 1 0

%Y Cf. A221125.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 02 2013

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Last modified February 27 19:09 EST 2024. Contains 370378 sequences. (Running on oeis4.)