A305680 Number of nX3 0..1 arrays with every element unequal to 0, 2, 3, 4, 5 or 6 king-move adjacent elements, with upper left element zero.

1, 8, 25, 139, 818, 4869, 29339, 177688, 1078090, 6547420, 39780381, 241739361, 1469140840, 8928868485, 54267151921, 329823144348, 2004595773274, 12183532071766, 74049126308943, 450056268717553, 2735355386324434

Offset

1,2

Comments

Column 3 of A305685.

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -3*a(n-2) -6*a(n-3) -61*a(n-4) -4*a(n-5) +53*a(n-6) +92*a(n-7) +78*a(n-8) -9*a(n-9) -8*a(n-10) -2*a(n-11) +8*a(n-12) +10*a(n-13) +2*a(n-14) for n>16

Example

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

Crossrefs

Cf. A305685.

Sequence in context: A275151 A302617 A042189 * A316927 A004246 A362276

Adjacent sequences: A305677 A305678 A305679 * A305681 A305682 A305683

Keyword

nonn

Author

R. H. Hardin, Jun 08 2018

Status

approved