A219137 - OEIS

%I #7 Jul 25 2018 05:35:37

%S 4,18,78,331,1400,5949,25277,107353,455938,1936500,8224877,34933256,

%T 148370893,630171269,2676507659,11367850562,48282330086,205068091043,

%U 870979546682,3699285278069,15711863292777,66732525229601

%N Unchanging value maps: number of n X 3 binary arrays indicating the locations of corresponding elements unequal to no horizontal, diagonal or antidiagonal neighbor in a random 0..2 n X 3 array.

%C Column 3 of A219142.

%H R. H. Hardin, <a href="/A219137/b219137.txt">Table of n, a(n) for n = 1..106</a>

%F Empirical: a(n) = 4*a(n-1) + a(n-2) + a(n-3) - 12*a(n-5) - 10*a(n-6) + 2*a(n-7) + 4*a(n-8).

%F Empirical g.f.: x*(4 + 2*x + 2*x^2 - 3*x^3 - 20*x^4 - 12*x^5 + 6*x^6 + 4*x^7) / (1 - 4*x - x^2 - x^3 + 12*x^5 + 10*x^6 - 2*x^7 - 4*x^8). - _Colin Barker_, Jul 25 2018

%e Some solutions for n=3:

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

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

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

%Y Cf. A219142.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 12 2012