A300968 Number of n X 3 0..1 arrays with every element equal to 1, 2, 3, 4 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

1, 11, 72, 459, 2956, 18996, 122043, 784108, 5037730, 32366408, 207947716, 1336022660, 8583679582, 55148432350, 354317698174, 2276420668626, 14625549576730, 93966244187418, 603714410892078, 3878744894728494

Offset

1,2

Comments

Column 3 of A300973.

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -2*a(n-2) -11*a(n-3) -a(n-4) +10*a(n-5) +6*a(n-6) -4*a(n-7) -4*a(n-8) -2*a(n-9) for n>11.

Example

Some solutions for n=5
..0..1..1. .0..1..1. .0..0..0. .0..1..1. .0..0..1. .0..0..0. .0..1..1
..0..1..1. .0..0..0. .0..1..1. .0..0..1. .0..1..1. .1..1..1. .0..1..1
..0..0..1. .0..0..0. .1..0..0. .0..1..0. .1..0..0. .0..0..0. .1..0..0
..0..1..0. .1..1..0. .0..1..0. .0..0..0. .0..1..0. .0..1..0. .0..0..1
..1..0..0. .1..0..0. .1..0..0. .1..1..1. .0..1..1. .0..1..0. .0..1..1

Crossrefs

Cf. A300973.

Sequence in context: A006975 A260585 A084900 * A218619 A197308 A142015

Adjacent sequences: A300965 A300966 A300967 * A300969 A300970 A300971

Keyword

nonn

Author

R. H. Hardin, Mar 17 2018

Status

approved