A302368 - OEIS

%I #4 Apr 06 2018 12:21:58

%S 2,2,12,20,72,168,496,1296,3616,9760,26816,73024,199808,545408,

%T 1490688,4071680,11125248,30392832,83037184,226857984,619792384,

%U 1693296640,4626182144,12638949376,34530271232,94338424832,257737408512

%N Number of 2Xn 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

%C Row 2 of A302367.

%H R. H. Hardin, <a href="/A302368/b302368.txt">Table of n, a(n) for n = 1..210</a>

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

%e Some solutions for n=5

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

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

%Y Cf. A302367.

%K nonn

%O 1,1

%A _R. H. Hardin_, Apr 06 2018