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A281058 Number of 3 X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 1

%I #8 Feb 15 2019 10:21:52

%S 0,6,68,239,618,1403,2828,5482,10342,19136,34907,62976,112617,199929,

%T 352771,619208,1081946,1882951,3265367,5644772,9730124,16728760,

%U 28693405,49108842,83882613,143016171,243420929,413658928,701916100,1189400585

%N Number of 3 X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

%H R. H. Hardin, <a href="/A281058/b281058.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 5*a(n-1) - 7*a(n-2) - 2*a(n-3) + 10*a(n-4) - 2*a(n-5) - 5*a(n-6) + a(n-7) + a(n-8) for n>15.

%F Empirical g.f.: x^2*(6 + 38*x - 59*x^2 - 89*x^3 + 62*x^4 - 51*x^5 + 175*x^6 + 166*x^7 - 217*x^8 - 106*x^9 + 71*x^10 + 21*x^11 - 7*x^12 - x^13) / ((1 - x)^2*(1 - x - x^2)^3). - _Colin Barker_, Feb 15 2019

%e Some solutions for n=4:

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

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

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

%Y Row 3 of A281056.

%K nonn

%O 1,2

%A _R. H. Hardin_, Jan 13 2017

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Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)