A295248 - OEIS

%I #4 Nov 18 2017 09:31:26

%S 7,35,183,948,4928,25596,132993,690938,3589717,18649981,96894136,

%T 503403630,2615382795,13587956889,70594857262,366768447408,

%U 1905508409402,9899876400759,51433807521668,267219149917538,1388310092601527

%N Number of nX3 0..1 arrays with each 1 horizontally or vertically adjacent to 0, 1 or 3 1s.

%C Column 3 of A295253.

%H R. H. Hardin, <a href="/A295248/b295248.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) +6*a(n-2) +a(n-3) +2*a(n-4) -6*a(n-5) -6*a(n-6) -18*a(n-7) -5*a(n-8) +3*a(n-9) +4*a(n-11) +a(n-12) +9*a(n-13) -a(n-14) +3*a(n-15) -3*a(n-16) -a(n-18)

%e Some solutions for n=7

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

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

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

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

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

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

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

%Y Cf. A295253.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 18 2017