A282372 - OEIS

%I #4 Feb 13 2017 11:06:52

%S 0,1,20,309,3499,33692,309493,2721044,23193721,193520569,1587628975,

%T 12850623027,102883527733,816204241881,6425192293124,50243446084946,

%U 390619259367639,3021431489931709,23265194042723056,178420043485112107

%N Number of nX3 0..1 arrays with no 1 equal to more than four of its king-move neighbors, with the exception of exactly two elements.

%C Column 3 of A282377.

%H R. H. Hardin, <a href="/A282372/b282372.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 15*a(n-1) -42*a(n-2) -112*a(n-3) -540*a(n-4) +2619*a(n-5) +10088*a(n-6) +24930*a(n-7) -11745*a(n-8) -121823*a(n-9) -302973*a(n-10) -109557*a(n-11) +626061*a(n-12) +1677252*a(n-13) +1111167*a(n-14) -1607654*a(n-15) -4968711*a(n-16) -3987444*a(n-17) +1869096*a(n-18) +8096727*a(n-19) +7157916*a(n-20) -59475*a(n-21) -6680688*a(n-22) -6454986*a(n-23) -1842524*a(n-24) +1900140*a(n-25) +2314704*a(n-26) +1190024*a(n-27) +304272*a(n-28) +37152*a(n-29) +1728*a(n-30)

%e Some solutions for n=4

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

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

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

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

%Y Cf. A282377.

%K nonn

%O 1,3

%A _R. H. Hardin_, Feb 13 2017