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A240784 Number of 3 X n 0..1 arrays with no element equal to fewer vertical neighbors than horizontal neighbors, with new values 0..1 introduced in row major order. 1

%I #8 Oct 29 2018 06:43:09

%S 4,11,20,46,97,216,472,1043,2296,5066,11169,24636,54332,119835,264300,

%T 582934,1285697,2835696,6254320,13794339,30424368,67103058,148000449,

%U 326425268,719953588,1587907627,3502240516,7724434622,17036776865

%N Number of 3 X n 0..1 arrays with no element equal to fewer vertical neighbors than horizontal neighbors, with new values 0..1 introduced in row major order.

%H R. H. Hardin, <a href="/A240784/b240784.txt">Table of n, a(n) for n = 1..210</a>

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

%F Empirical g.f.: x*(4 + 3*x - 6*x^2 - x^3 - 4*x^4) / ((1 - x)*(1 + x)*(1 - 2*x - x^3)). - _Colin Barker_, Oct 29 2018

%e Some solutions for n=4:

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

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

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

%Y Row 3 of A240783.

%K nonn

%O 1,1

%A _R. H. Hardin_, Apr 12 2014

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Last modified April 18 02:22 EDT 2024. Contains 371767 sequences. (Running on oeis4.)