A281831 Number of nX2 0..1 arrays with no element equal to more than four of its king-move neighbors and with new values introduced in order 0 sequentially upwards.

2, 8, 31, 121, 472, 1841, 7181, 28010, 109255, 426157, 1662256, 6483749, 25290329, 98646746, 384778723, 1500857065, 5854200856, 22834731209, 89068510325, 347418126314, 1355129372335, 5285779516597, 20617562919424, 80420286052733

Offset

1,1

Comments

Column 2 of A281837.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +3*a(n-2) +2*a(n-3)

Example

Some solutions for n=4
..0..0. .0..0. .0..1. .0..0. .0..0. .0..0. .0..0. .0..1. .0..0. .0..1
..0..1. .0..0. .1..0. .1..0. .1..0. .1..1. .1..1. .1..0. .1..0. .0..1
..0..0. .0..1. .1..1. .0..1. .1..1. .0..1. .0..1. .1..0. .0..1. .1..1
..0..0. .0..0. .1..0. .0..0. .0..0. .0..0. .0..1. .1..1. .0..1. .1..1

Crossrefs

Cf. A281837.

Sequence in context: A077838 A216318 A018916 * A206229 A027073 A150793

Adjacent sequences: A281828 A281829 A281830 * A281832 A281833 A281834

Keyword

nonn

Author

R. H. Hardin, Jan 31 2017

Status

approved