|
%I #9 Feb 16 2019 12:25:00
%S 2,28,98,270,676,1588,3604,7960,17254,36848,77776,162610,337292,
%T 694982,1423852,2902806,5892558,11916410,24017514,48262212,96719706,
%U 193358890,385702166,767826768,1525708160,3026506470,5994196442,11854696726
%N Number of n X 4 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.
%H R. H. Hardin, <a href="/A281201/b281201.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 2*a(n-1) + 3*a(n-2) - 4*a(n-3) - 6*a(n-4) + 2*a(n-5) + 4*a(n-6) - a(n-8).
%F Empirical g.f.: 2*x*(1 + x)*(1 + 11*x + 7*x^2 - 8*x^3 - 9*x^4 + 2*x^6) / (1 - x - 2*x^2 + x^4)^2. - _Colin Barker_, Feb 16 2019
%e Some solutions for n=4:
%e ..0..0..1..0. .0..0..1..1. .0..0..1..1. .0..1..0..1. .0..1..0..1
%e ..1..0..1..1. .1..0..0..1. .1..0..0..0. .0..1..1..0. .0..1..0..1
%e ..1..0..0..0. .1..1..0..1. .1..0..1..0. .0..0..1..0. .1..0..1..0
%e ..1..0..1..1. .0..1..1..1. .1..0..1..0. .1..0..1..1. .1..0..0..0
%Y Column 4 of A281205.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 17 2017
|
