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A304922 Number of nX4 0..1 arrays with every element unequal to 0, 1, 2, 5 or 7 king-move adjacent elements, with upper left element zero. 1
8, 9, 31, 87, 266, 851, 2510, 7348, 21910, 65581, 195382, 581778, 1734115, 5169644, 15407810, 45920848, 136868173, 407941876, 1215873162, 3623912739, 10801114566, 32192856740, 95951141082, 285983353689, 852376442742, 2540517125174 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 4 of A304926.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +2*a(n-3) -4*a(n-4) -6*a(n-5) -6*a(n-6) -a(n-7) +23*a(n-8) -12*a(n-9) +4*a(n-10) +8*a(n-11) -2*a(n-12) -8*a(n-13) for n>18
EXAMPLE
Some solutions for n=5
..0..0..1..0. .0..1..0..0. .0..0..1..0. .0..0..0..0. .0..1..0..0
..1..0..0..0. .0..0..0..1. .1..0..0..0. .1..0..0..1. .0..0..0..0
..0..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..0
..0..0..0..1. .0..0..0..0. .1..0..0..0. .0..0..0..1. .1..0..0..0
..0..0..0..0. .0..0..1..0. .0..0..0..0. .0..0..0..0. .0..0..1..0
CROSSREFS
Cf. A304926.
Sequence in context: A316416 A303262 A225364 * A181900 A371443 A038344
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 21 2018
STATUS
approved

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Last modified June 21 06:38 EDT 2024. Contains 373540 sequences. (Running on oeis4.)