A185460 Number of (n+1) X 3 binary arrays with no 2 X 2 subblock determinant equal to any horizontal or vertical neighbor 2 X 2 subblock determinant.

34, 92, 240, 672, 1646, 4452, 11050, 29506, 74092, 195978, 496142, 1303446, 3318830, 8676824, 22183736, 57796628, 148199862, 385159228, 989675770, 2567545726, 6607214940, 17119703570, 44102038206, 114168385010, 294332423078

Offset

1,1

Comments

Column 2 of A185467.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 5*a(n-2) + 4*a(n-3) + 4*a(n-4) - 8*a(n-5) - a(n-6) + 3*a(n-8) for n>10.

Empirical g.f.: 2*x*(17 + 46*x + 35*x^2 + 38*x^3 - 29*x^4 + 18*x^5 - 29*x^6 - 7*x^7 - 18*x^8 + 2*x^9) / (1 - 5*x^2 - 4*x^3 - 4*x^4 + 8*x^5 + x^6 - 3*x^8). - Colin Barker, Apr 15 2018

Example

Some solutions for 5 X 3:
..1..1..0....1..1..1....1..1..0....1..1..1....0..1..0....0..1..0....0..0..1
..0..1..0....0..1..0....0..1..0....0..1..0....1..1..1....0..1..1....0..1..0
..1..0..1....1..1..1....1..0..1....1..1..0....0..1..1....1..1..1....1..0..1
..0..1..1....0..1..0....0..1..0....1..1..1....0..1..0....1..1..0....1..1..0
..0..0..1....1..0..1....0..0..1....1..0..0....1..0..0....1..0..0....0..0..1

Crossrefs

Cf. A185467.

Sequence in context: A067977 A183311 A282811 * A260467 A202421 A202414

Adjacent sequences: A185457 A185458 A185459 * A185461 A185462 A185463

Keyword

nonn

Author

R. H. Hardin, Jan 28 2011

Status

approved