|
%I #4 Jan 06 2018 10:54:58
%S 1,17,48,146,399,1114,3124,8861,25130,71196,201467,570100,1613454,
%T 4566805,12926144,36586306,103553095,293094410,829569532,2348002541,
%U 6645755138,18810052924,53239705819,150688904948,426507740022
%N Number of nX3 0..1 arrays with every element equal to 1, 2 or 3 king-move adjacent elements, with upper left element zero.
%C Column 3 of A297823.
%H R. H. Hardin, <a href="/A297818/b297818.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) -a(n-2) -a(n-3) +7*a(n-4) -a(n-5) +2*a(n-6) +2*a(n-7) +2*a(n-9) for n>11
%e Some solutions for n=7
%e ..0..1..0. .0..1..0. .0..0..1. .0..0..1. .0..0..1. .0..1..1. .0..0..0
%e ..0..0..1. .1..0..0. .1..1..1. .1..1..1. .1..1..0. .1..0..1. .1..1..1
%e ..1..1..1. .1..1..1. .0..0..0. .0..0..0. .0..0..1. .1..0..1. .1..0..0
%e ..0..0..0. .0..0..0. .1..1..1. .0..1..1. .1..1..0. .0..0..1. .0..1..0
%e ..0..1..1. .1..1..0. .1..0..0. .1..0..1. .0..1..0. .1..1..1. .0..1..0
%e ..1..0..1. .0..1..1. .1..0..1. .0..1..0. .0..1..0. .0..0..0. .1..1..0
%e ..1..0..1. .0..0..0. .1..1..0. .0..0..1. .0..1..0. .1..1..1. .0..0..1
%Y Cf. A297823.
%K nonn
%O 1,2
%A _R. H. Hardin_, Jan 06 2018
| 