A204296 Number of nX3 0..3 arrays with every element neighboring horizontally or vertically both a 0 and a 1, and 2 introduced before 3 in row major order

0, 4, 80, 160, 2816, 19540, 164112, 1490212, 13307116, 115013704, 1026915800, 9058997060, 80167041712, 709913397236, 6286420634340, 55643072420896, 492719871262640, 4362369370725028, 38624679802279760, 341986732942120852

Offset

1,2

Comments

Column 3 of A204301

Links

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

Formula

Empirical: a(n) = 14*a(n-1) -45*a(n-2) -16*a(n-3) +78*a(n-4) +114*a(n-5) +6697*a(n-6) -85640*a(n-7) +279283*a(n-8) -16480*a(n-9) +28340*a(n-10) -2602296*a(n-11) +1904440*a(n-12) +9632160*a(n-13) -17494992*a(n-14) -22563776*a(n-15) +18380928*a(n-16) +183274752*a(n-17) -152036992*a(n-18) -324779008*a(n-19) -146074432*a(n-20) +1486973440*a(n-21) -836087552*a(n-22) -31606272*a(n-23) +421416960*a(n-24) -266897408*a(n-25) for n>28

Example

Some solutions for n=5
..1..0..2....2..0..1....1..0..0....0..0..1....1..0..0....1..1..1....0..0..1
..1..0..1....1..0..1....1..1..1....1..1..1....1..1..1....0..0..0....1..1..1
..0..2..1....1..3..1....0..0..2....2..2..0....0..2..3....1..1..0....2..0..0
..0..1..0....0..0..0....0..1..0....0..1..0....0..1..0....0..0..0....1..1..1
..2..1..0....1..1..0....3..1..0....0..1..3....3..1..0....0..1..1....0..0..2

Crossrefs

Sequence in context: A018807 A216410 A125710 * A192790 A211152 A093854

Adjacent sequences: A204293 A204294 A204295 * A204297 A204298 A204299

Keyword

nonn

Author

R. H. Hardin Jan 14 2012

Status

approved