login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

Number of nX3 0..1 arrays with every element unequal to 1, 2, 4, 5, 7 or 8 king-move adjacent elements, with upper left element zero.
1

%I #4 Jul 09 2018 11:24:53

%S 1,11,15,33,117,247,599,1757,4241,10783,29239,74521,192273,508375,

%T 1317567,3422449,8971629,23370303,60880867,159136445,415145389,

%U 1082772235,2827552935,7379387077,19255943685,50269166119,131207698359

%N Number of nX3 0..1 arrays with every element unequal to 1, 2, 4, 5, 7 or 8 king-move adjacent elements, with upper left element zero.

%C Column 3 of A316648.

%H R. H. Hardin, <a href="/A316643/b316643.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) +4*a(n-2) +13*a(n-3) -13*a(n-4) -46*a(n-5) -59*a(n-6) +53*a(n-7) +153*a(n-8) +98*a(n-9) -60*a(n-10) -140*a(n-11) -7*a(n-12) +67*a(n-13) +15*a(n-14) -78*a(n-15) -48*a(n-16) -32*a(n-17)

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A316648.

%K nonn

%O 1,2

%A _R. H. Hardin_, Jul 09 2018