A303470 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 2, 3, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 32, 170, 948, 5237, 29009, 160590, 888993, 4921496, 27244949, 150826626, 834967061, 4622327859, 25588933014, 141658809728, 784214751260, 4341366231543, 24033545332699, 133048277989004, 736547356196655

Offset

1,1

Comments

Row 3 of A303469.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +15*a(n-2) -32*a(n-4) +5*a(n-5) +53*a(n-6) -14*a(n-7) -10*a(n-8) +19*a(n-9) -5*a(n-10) +8*a(n-11) +a(n-12) -4*a(n-13) -2*a(n-14) for n>15

Example

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

Crossrefs

Cf. A303469.

Sequence in context: A271149 A271201 A302809 * A222507 A270153 A271306

Adjacent sequences: A303467 A303468 A303469 * A303471 A303472 A303473

Keyword

nonn

Author

R. H. Hardin, Apr 24 2018

Status

approved