A251252 - OEIS

%I #8 Nov 27 2018 09:08:33

%S 18,56,150,446,1232,3602,10108,29272,82854,238640,678658,1948718,

%T 5556204,15926754,45474920,130227048,372121034,1065071288,3044724350,

%U 8711869630,24910552504,71264572098,203799138404,582977750488,1667293062110

%N Number of (n+1) X (2+1) 0..1 arrays with every 2 X 2 subblock having a single 1 or two 1s on the same edge.

%H R. H. Hardin, <a href="/A251252/b251252.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) + 4*a(n-2) - 14*a(n-3) + 3*a(n-4) + 3*a(n-5).

%F Empirical g.f.: 2*x*(9 + x - 45*x^2 + 12*x^3 + 12*x^4) / (1 - 3*x - 4*x^2 + 14*x^3 - 3*x^4 - 3*x^5). - _Colin Barker_, Nov 27 2018

%e Some solutions for n=4:

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

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

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

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

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

%Y Column 2 of A251258.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 01 2014