A303041 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 3, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 6, 14, 28, 56, 150, 360, 828, 1906, 4628, 10972, 25850, 60948, 145152, 343870, 814072, 1927632, 4573086, 10836712, 25678860, 60851842, 144253956, 341881772, 810275098, 1920403380, 4551789280, 10788216718, 25569422984, 60602792000

Offset

1,1

Comments

Row 3 of A303040.

Links

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

Formula

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

Example

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

Crossrefs

Cf. A303040.

Sequence in context: A030138 A369684 A009849 * A103419 A005202 A342602

Adjacent sequences: A303038 A303039 A303040 * A303042 A303043 A303044

Keyword

nonn

Author

R. H. Hardin, Apr 17 2018

Status

approved