|
%I #11 Nov 09 2018 05:08:19
%S 2,3,6,10,21,42,86,179,370,770,1601,3330,6930,14419,30006,62442,
%T 129941,270410,562726,1171043,2436962,5071362,10553601,21962242,
%U 45703842,95110563,197926886,411889610,857150101,1783745642,3712008566,7724760339
%N Number of n X 2 0..1 arrays with no element equal to exactly two horizontal and vertical neighbors, with new values 0..1 introduced in row major order.
%C Column 2 of A240519.
%H R. H. Hardin, <a href="/A240513/b240513.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) - 2*a(n-4) + a(n-5).
%F Empirical g.f.: x*(2 - x)*(1 - x^2 - 2*x^3) / ((1 - x)*(1 - x - 2*x^2 - x^3 + x^4)). - _Colin Barker_, Feb 24 2018
%F Empirical: a(n) = 1+A105309(n). - _R. J. Mathar_, Nov 09 2018
%e All solutions for n=4:
%e ..0..1....0..1....0..1....0..1....0..0....0..1....0..1....0..1....0..1....0..1
%e ..0..0....0..1....1..0....0..1....1..1....1..0....1..1....1..0....1..0....1..0
%e ..0..1....1..0....1..1....1..0....0..0....1..0....0..1....0..1....0..0....0..1
%e ..1..0....1..0....1..0....0..1....1..1....0..1....1..0....1..0....1..0....0..1
%Y Cf. A240519.
%K nonn
%O 1,1
%A _R. H. Hardin_, Apr 06 2014
|
