A305035 - OEIS

A305035

Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 6 or 7 king-move adjacent elements, with upper left element zero.

4, 3, 7, 7, 13, 23, 37, 63, 109, 183, 309, 527, 893, 1511, 2565, 4351, 7373, 12503, 21205, 35951, 60957, 103367, 175269, 297183, 503917, 854455, 1448821, 2456655, 4165565, 7063207, 11976517, 20307647, 34434061, 58387095, 99002389, 167870511

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Column 3 of A305040.

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) +2*a(n-3) for n>6

EXAMPLE

Some solutions for n=5

..0..0..0. .0..0..1. .0..0..0. .0..0..0. .0..1..1. .0..0..0. .0..0..0

..0..0..0. .0..1..0. .0..1..0. .0..0..0. .1..0..1. .0..0..0. .0..0..0

..0..0..0. .0..0..0. .0..1..0. .0..1..0. .1..1..1. .0..0..0. .0..0..0

..0..0..0. .0..0..0. .0..0..0. .0..1..0. .1..0..1. .0..1..0. .0..1..0

..0..0..0. .0..0..0. .0..0..0. .0..0..0. .1..1..0. .1..0..0. .0..0..1

CROSSREFS

Cf. A305040.

Sequence in context: A168200 A112887 A351684 * A352832 A010654 A244335

Adjacent sequences: A305032 A305033 A305034 * A305036 A305037 A305038

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 24 2018

STATUS

approved