A185461 Number of (n+1) X 4 binary arrays with no 2 X 2 subblock determinant equal to any horizontal or vertical neighbor 2 X 2 subblock determinant.

92, 240, 866, 2766, 8762, 27102, 83688, 258056, 795746, 2453840, 7566872, 23333794, 71953944, 221882868, 684215602, 2109901528, 6506259672, 20063218306, 61868531104, 190782709036, 588312691858, 1814167673456, 5594311312512

Offset

1,1

Comments

Column 3 of A185467.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 2*a(n-2) + 3*a(n-3) + 2*a(n-4) + 4*a(n-5) + 2*a(n-6) for n>12.

Empirical g.f.: 2*x*(46 + 28*x + 101*x^2 + 139*x^3 + 297*x^4 + 300*x^5 + 393*x^6 + 357*x^7 + 316*x^8 + 194*x^9 + 112*x^10 + 32*x^11) / (1 - 2*x - 2*x^2 - 3*x^3 - 2*x^4 - 4*x^5 - 2*x^6). - Colin Barker, Apr 15 2018

Example

Some solutions for 3 X 4:
..0..1..1..1....1..0..0..1....1..0..1..0....1..1..1..1....0..0..1..0
..1..1..1..0....1..1..1..1....0..1..0..1....1..0..1..1....1..1..0..1
..0..1..0..0....0..0..1..1....1..1..1..1....1..1..0..1....1..0..1..0

Crossrefs

Cf. A185467.

Sequence in context: A044424 A044805 A063326 * A246802 A302351 A100169

Adjacent sequences: A185458 A185459 A185460 * A185462 A185463 A185464

Keyword

nonn

Author

R. H. Hardin, Jan 28 2011

Status

approved