A207414 Number of nX3 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 1 1 and 1 0 1 vertically

6, 36, 92, 241, 720, 1889, 4719, 12102, 30414, 74588, 182737, 445468, 1075185, 2583413, 6187826, 14753420, 35052328, 83069841, 196345572, 462972905, 1089545883, 2559508250, 6002666694, 14057272936, 32876868289, 76799290072

Offset

1,1

Comments

Column 3 of A207419

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -4*a(n-2) +7*a(n-3) -21*a(n-4) +7*a(n-5) -a(n-6) +33*a(n-7) +7*a(n-8) -13*a(n-9) -35*a(n-10) -7*a(n-11) +9*a(n-12) +17*a(n-13) +4*a(n-14) -3*a(n-15) -3*a(n-16)

Example

Some solutions for n=4
..1..0..1....1..0..0....0..1..1....0..0..0....1..0..0....1..1..1....0..1..1
..0..1..1....0..0..0....0..1..1....0..1..1....0..1..1....1..1..1....1..0..0
..0..0..0....0..1..1....0..1..1....0..0..0....0..0..0....0..1..1....0..0..0
..1..0..0....0..0..0....1..1..1....0..0..0....0..0..0....0..1..1....0..0..0

Crossrefs

Sequence in context: A080857 A108158 A207559 * A192278 A207106 A207306

Adjacent sequences: A207411 A207412 A207413 * A207415 A207416 A207417

Keyword

nonn

Author

R. H. Hardin Feb 17 2012

Status

approved