A317431 Number of nX3 0..1 arrays with every element unequal to 1, 2, 3, 5, 6, 7 or 8 king-move adjacent elements, with upper left element zero.

1, 16, 61, 201, 863, 3666, 14831, 61638, 255772, 1057307, 4380003, 18147665, 75156794, 311315739, 1289593418, 5341744958, 22126877953, 91655931185, 379663396847, 1572669053056, 6514430280073, 26984558653702, 111777454797820

Offset

1,2

Comments

Column 3 of A317436.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +5*a(n-2) +10*a(n-3) -29*a(n-4) -69*a(n-5) -36*a(n-6) +68*a(n-7) +201*a(n-8) +115*a(n-9) +35*a(n-10) -218*a(n-11) -192*a(n-12) -83*a(n-13) +2*a(n-14) +113*a(n-15) +61*a(n-16) +18*a(n-17) +4*a(n-18) -10*a(n-19) -4*a(n-20) for n>21

Example

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

Crossrefs

Cf. A317436.

Sequence in context: A031190 A043229 A044009 * A241523 A264632 A373667

Adjacent sequences: A317428 A317429 A317430 * A317432 A317433 A317434

Keyword

nonn

Author

R. H. Hardin, Jul 27 2018

Status

approved