A306124 - OEIS

%I #6 Oct 13 2021 14:57:11

%S 3,7,9,19,39,73,147,319,681,1451,3127,6789,14887,32963,73569,165355,

%T 374119,851749,1949959,4486007,10364533,24034895,55913671,130430861,

%U 304967127,714466543,1676614357,3939963499,9269602859,21830156705

%N Number of n X 3 0..1 arrays with every element unequal to 0, 1, 3, 4, 6 or 7 king-move adjacent elements, with upper left element zero.

%C Column 3 of A306129.

%H R. H. Hardin, <a href="/A306124/b306124.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) -a(n-3) -7*a(n-4) +4*a(n-5) -4*a(n-6) -7*a(n-8) +9*a(n-9) +14*a(n-10) +11*a(n-11) -7*a(n-12) -6*a(n-13).

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A306129.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jun 22 2018