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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
4, 14, 47, 156, 548, 1970, 7049, 25364, 91307, 328700, 1183518, 4261468, 15344635, 55253618, 198959548, 716424463, 2579743890, 9289300111, 33449490192, 120447025154, 433713239426, 1561742028021, 5623619418043, 20249884464928 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 3 of A320409.
LINKS
FORMULA
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
EXAMPLE
Some solutions for n=5
..0..0..1. .0..1..1. .0..1..1. .0..1..0. .0..0..0. .0..0..1. .0..0..0
..0..0..1. .1..0..0. .1..1..1. .0..0..0. .0..1..0. .0..1..1. .1..1..0
..0..0..1. .1..0..0. .1..1..1. .0..0..0. .1..0..1. .1..1..0. .1..0..0
..1..1..1. .1..0..0. .0..1..1. .0..0..0. .1..1..1. .1..1..1. .0..0..1
..1..1..1. .1..0..0. .1..1..1. .0..1..0. .1..1..1. .1..1..1. .0..0..0
CROSSREFS
Cf. A320409.
Sequence in context: A273714 A082574 A289780 * A137284 A365987 A228178
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 12 2018
STATUS
approved

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Last modified February 20 18:38 EST 2024. Contains 370217 sequences. (Running on oeis4.)