A295525 - OEIS

%I #8 Feb 21 2018 14:40:31

%S 2,10,29,87,280,876,2735,8583,26900,84274,264107,827651,2593568,

%T 8127490,25469197,79812833,250109752,783769936,2456102483,7696696911,

%U 24119166438,75582316528,236852570799,742225734425,2325915393694,7288729246884

%N Number of n X 2 0..1 arrays with each 1 horizontally or vertically adjacent to 1, 2 or 4 1s.

%C Column 2 of A295531.

%H R. H. Hardin, <a href="/A295525/b295525.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) + 2*a(n-2) + 5*a(n-3) - a(n-5) - a(n-6).

%F Empirical g.f.: x*(2 + 6*x + 5*x^2 - x^3 - 2*x^4 - x^5) / (1 - 2*x - 2*x^2 - 5*x^3 + x^5 + x^6). - _Colin Barker_, Feb 21 2018

%e Some solutions for n=5:

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

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

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

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

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

%Y Cf. A295531.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 23 2017