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.

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

Offset

1,1

Comments

Column 4 of A304926.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

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 A380009 A371443

Adjacent sequences: A304919 A304920 A304921 * A304923 A304924 A304925

Keyword

nonn

Author

R. H. Hardin, May 21 2018

Status

approved