A181025 Maximum number of 1s in an nX(n+1) binary matrix with no four 1s adjacent in a line along a row, column or diagonally.

2, 6, 9, 15, 22, 31, 39

Offset

1,1

Links

Table of n, a(n) for n=1..7.

Example

Some solutions for 6X7
..1..1..1..0..1..1..1....1..1..1..0..1..1..1....1..1..1..0..1..1..1
..1..1..1..0..1..1..1....1..1..1..0..1..1..1....1..1..1..0..1..1..1
..1..1..0..0..0..1..0....1..1..0..0..0..1..1....1..0..1..1..1..0..0
..0..0..1..1..1..0..1....0..0..1..1..1..0..0....0..1..0..0..0..1..1
..1..1..1..0..1..1..1....1..1..1..0..1..1..1....1..1..1..0..1..1..1
..1..1..1..0..1..1..1....1..1..1..0..1..1..1....1..1..1..0..1..1..1

Crossrefs

Superdiagonal 1 of A181024.

Sequence in context: A084140 A294864 A103139 * A345051 A265202 A355738

Adjacent sequences: A181022 A181023 A181024 * A181026 A181027 A181028

Keyword

nonn,more

Author

R. H. Hardin, Sep 30 2010

Status

approved