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A320404 Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 4 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. 1

%I #4 Oct 12 2018 12:34:59

%S 4,14,47,156,548,1970,7049,25364,91307,328700,1183518,4261468,

%T 15344635,55253618,198959548,716424463,2579743890,9289300111,

%U 33449490192,120447025154,433713239426,1561742028021,5623619418043,20249884464928

%N Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 4 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

%C Column 3 of A320409.

%H R. H. Hardin, <a href="/A320404/b320404.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) +a(n-2) -6*a(n-3) -7*a(n-4) -18*a(n-5) +15*a(n-6) +23*a(n-7) +67*a(n-8) -3*a(n-9) -72*a(n-10) -53*a(n-11) -44*a(n-12) +47*a(n-13) +23*a(n-14) +23*a(n-15) +37*a(n-16) -20*a(n-17) -8*a(n-18) -12*a(n-19) -8*a(n-20) +13*a(n-21) +2*a(n-22) -3*a(n-23) for n>25

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A320409.

%K nonn

%O 1,1

%A _R. H. Hardin_, Oct 12 2018

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Last modified April 16 17:00 EDT 2024. Contains 371749 sequences. (Running on oeis4.)