A181037 Number of nX3 binary matrices with no initial bit string in any row or column divisible by 6

1, 3, 6, 18, 41, 112, 269, 703, 1729, 4427, 11010, 27923, 69819, 176278, 441932, 1113390, 2794963, 7034179, 17669820, 44447034, 111689337

Offset

1,2

Comments

Column 3 of A181039

Links

Table of n, a(n) for n=1..21.

Formula

Empirical G.f.: -1 + (1-x)*(1+x)*(-1 + 6*x^2 - x^3 - 10*x^4 + x^5 + 3*x^6)/(-1 + x + 9*x^2 - 7*x^3 - 24*x^4 + 16*x^5 + 20*x^6 - 11*x^7 - 3*x^8 + x^9). - Vaclav Kotesovec, Nov 30 2012

Example

Some solutions for 6X3
..1..1..1....1..1..1....1..1..1....1..1..1....1..1..1....1..1..1....1..1..1
..1..0..0....1..0..0....1..1..1....1..1..1....1..0..1....1..0..0....1..1..1
..1..1..1....1..0..0....1..1..1....1..1..1....1..1..1....1..1..1....1..1..1
..1..1..1....1..0..0....1..0..1....1..0..1....1..0..0....1..1..1....1..0..0
..1..0..0....1..0..0....1..1..1....1..0..1....1..0..0....1..1..1....1..1..1
..1..1..1....1..0..0....1..0..0....1..1..1....1..0..1....1..0..0....1..0..0

Crossrefs

Sequence in context: A362014 A216813 A356766 * A222856 A342583 A007990

Adjacent sequences: A181034 A181035 A181036 * A181038 A181039 A181040

Keyword

nonn

Author

R. H. Hardin Sep 30 2010

Status

approved