A181219 Number of nX3 binary matrices with no three 1's adjacent in a line horizontally, vertically, diagonally or antidiagonally

7, 49, 230, 1209, 6475, 34020, 179097, 944514, 4978956, 26241679, 138316703, 729070278, 3842881010, 20255521442, 106765644778, 562755120940, 2966245831625, 15634892911279, 82410528967137, 434380653636920

Offset

1,1

Comments

Column 3 of A181224

Links

R. H. Hardin, Table of n, a(n) for n=1..350

Formula

Empirical: a(n)=2*a(n-1)+8*a(n-2)+38*a(n-3)+51*a(n-4)+41*a(n-5)-48*a(n-6)-88*a(n-7)-4*a(n-8)-8*a(n-9)-15*a(n-10)+14*a(n-11)-7*a(n-12)+a(n-13)-2*a(n-14)

Example

Some avoided solutions for 4X3
..1..0..0....1..1..0....1..0..0....1..0..0....0..0..1....0..0..0....0..0..1
..0..1..0....0..1..0....0..0..1....0..1..0....0..1..0....0..0..0....0..1..0
..0..0..1....0..0..1....0..1..0....0..0..1....1..0..1....0..0..1....1..0..0
..0..1..0....0..0..0....1..0..0....1..0..0....0..0..0....1..1..1....0..0..1

Crossrefs

Sequence in context: A188517 A206878 A206780 * A141783 A181479 A223842

Adjacent sequences: A181216 A181217 A181218 * A181220 A181221 A181222

Keyword

nonn

Author

R. H. Hardin Oct 10 2010

Status

approved