A300349 - OEIS

%I #6 May 02 2023 15:21:13

%S 8,223,306,729,1496,3092,5451,12038,22852,46541,95132,196177,405629,

%T 840634,1744597,3623639,7531533,15660855,32571028,67753153,140956422,

%U 293282485,610274374,1269978478,2642991878,5500729098,11448984844

%N Number of n X 7 0..1 arrays with every element equal to 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

%C Column 7 of A300350.

%H R. H. Hardin, <a href="/A300349/b300349.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 5*a(n-1) -8*a(n-2) +4*a(n-3) +a(n-8) -3*a(n-9) +4*a(n-10) -2*a(n-11) +a(n-12) -a(n-13) -a(n-18) +a(n-19) for n>25.

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A300350.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 03 2018