A183435 Number of n X 2 binary arrays with every 1 having exactly one king-move neighbor equal to 1.

2, 7, 13, 28, 69, 149, 330, 755, 1681, 3756, 8457, 18937, 42418, 95183, 213349, 478204, 1072285, 2403885, 5388986, 12082011, 27086537, 60724492, 136139073, 305209713, 684246754, 1534012759, 3439098365, 7710098140, 17285247541, 38751739141

Offset

1,1

Comments

Column 2 of A183442.

Links

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

Formula

Empirical: a(n) = a(n-1) + a(n-2) + 4*a(n-3).

Empirical g.f.: x*(2 + 5*x + 4*x^2) / (1 - x - x^2 - 4*x^3). - Colin Barker, Feb 27 2018

Example

Some solutions for 3 X 2:
  1 1   0 1   1 0   0 0   1 1   1 0   0 0   0 0   0 0   0 0
  0 0   1 0   0 1   1 0   0 0   1 0   1 1   0 1   0 0   0 0
  0 0   0 0   0 0   0 1   1 1   0 0   0 0   0 1   0 0   1 1

Crossrefs

Cf. A183442.

Sequence in context: A182415 A275491 A360673 * A360385 A141777 A297883

Adjacent sequences: A183432 A183433 A183434 * A183436 A183437 A183438

Keyword

nonn

Author

R. H. Hardin, Jan 04 2011

Status

approved