A301486 - OEIS

%I #4 Mar 22 2018 11:45:58

%S 4,18,52,148,441,1372,4326,13641,42741,133208,414303,1289070,4015530,

%T 12519594,39044533,121754095,379591807,1183290025,3688511653,

%U 11498007929,35843459506,111739411177,348340800464,1085925223300,3385266114712

%N Number of nX3 0..1 arrays with every element equal to 0, 1, 2, 4, 5 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

%C Column 3 of A301491.

%H R. H. Hardin, <a href="/A301486/b301486.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 8*a(n-1) -22*a(n-2) +15*a(n-3) +44*a(n-4) -86*a(n-5) +a(n-6) +87*a(n-7) -13*a(n-8) -39*a(n-9) +19*a(n-10) -56*a(n-11) -26*a(n-12) +38*a(n-13) +90*a(n-14) +118*a(n-15) -46*a(n-16) -18*a(n-17) -120*a(n-18) -6*a(n-19) -15*a(n-20) +26*a(n-21) +3*a(n-23) -a(n-24) for n>25

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A301491.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 22 2018