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A219422 Unchanging value maps: number of 2 X n binary arrays indicating the locations of corresponding elements unequal to no horizontal or antidiagonal neighbor in a random 0..2 2 X n array. 1

%I

%S 1,7,20,57,160,454,1292,3676,10452,29724,84548,240480,683968,1945348,

%T 5533040,15737260,44760324,127308564,362094824,1029880752,2929216636,

%U 8331363064,23696305892,67397723860,191694568548,545223274608

%N Unchanging value maps: number of 2 X n binary arrays indicating the locations of corresponding elements unequal to no horizontal or antidiagonal neighbor in a random 0..2 2 X n array.

%C Row 2 of A219421.

%H R. H. Hardin, <a href="/A219422/b219422.txt">Table of n, a(n) for n = 1..210</a>

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

%F Empirical g.f.: x*(1 + 5*x + 5*x^2 + 7*x^3 + x^4 - 9*x^5 - 9*x^6 - 2*x^7) / ((1 + 2*x^2)*(1 - 2*x - 3*x^2 + x^3 + 2*x^4)). - _Colin Barker_, Jul 26 2018

%e Some solutions for n=3:

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

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

%Y Cf. A219421.

%K nonn

%O 1,2

%A _R. H. Hardin_, Nov 19 2012

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Last modified May 17 04:33 EDT 2022. Contains 353730 sequences. (Running on oeis4.)