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 A233157 Number of 4 X n 0..2 arrays with no element x(i,j) adjacent to value 2-x(i,j) horizontally or antidiagonally. 1

%I #8 Oct 09 2018 14:57:30

%S 81,384,2592,17496,121176,842616,5871528,40931568,285366888,

%T 1989557640,13871104848,96708780360,674249796360,4700843090928,

%U 32774093555112,228499694410248,1593090904911120,11106967289377032,77437340197187976

%N Number of 4 X n 0..2 arrays with no element x(i,j) adjacent to value 2-x(i,j) horizontally or antidiagonally.

%H R. H. Hardin, <a href="/A233157/b233157.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 9*a(n-1) - 15*a(n-2) + 6*a(n-3) for n>7.

%F Empirical g.f.: 3*x*(27 - 115*x + 117*x^2 - 186*x^3 + 96*x^4 - 360*x^5 + 216*x^6) / (1 - 9*x + 15*x^2 - 6*x^3). - _Colin Barker_, Oct 09 2018

%e Some solutions for n=5:

%e ..0..1..0..0..0....1..2..2..1..2....0..0..1..2..1....2..1..0..0..1

%e ..0..0..0..0..0....2..1..2..2..2....1..2..1..0..1....0..0..1..2..1

%e ..1..0..0..0..0....2..2..2..2..1....1..0..1..2..2....0..0..1..2..1

%e ..0..1..0..0..1....2..1..2..2..2....1..2..1..2..2....1..0..1..0..1

%Y Row 4 of A233155.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 05 2013

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Last modified June 13 05:35 EDT 2024. Contains 373366 sequences. (Running on oeis4.)