A301885 - OEIS

%I #4 Mar 28 2018 10:59:41

%S 2,5,10,18,35,74,154,317,658,1370,2851,5930,12338,25677,53434,111194,

%T 231395,481538,1002090,2085365,4339682,9030962,18793603,39109842,

%U 81388322,169370645,352463530,733483298,1526392675,3176452154,6610257274

%N Number of 2Xn 0..1 arrays with every element equal to 0, 1 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero.

%C Row 2 of A301884.

%H R. H. Hardin, <a href="/A301885/b301885.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) +a(n-3) -a(n-4) -2*a(n-6) +a(n-7)

%e Some solutions for n=5

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

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

%Y Cf. A301884.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 28 2018