A228749 Number of n X n binary arrays with top left element equal to 1 and no two ones adjacent horizontally or antidiagonally.

1, 3, 39, 780, 43862, 4823826, 1316714732, 762713002760, 1040109467257908, 3118624187066762728, 21501868781585259257676, 331091404725670052219822756, 11603262095526618070600084170304, 914315533886530112431287075923892544

Offset

1,2

Comments

Diagonal of A228754

Links

R. H. Hardin, Table of n, a(n) for n = 1..30

Example

Some solutions for n=4
..1..0..0..0....1..0..0..1....1..0..0..0....1..0..1..0....1..0..0..0
..1..0..0..0....0..1..0..0....0..0..0..1....0..0..1..0....1..0..1..0
..0..1..0..1....0..0..0..1....0..1..0..0....1..0..0..1....1..0..1..0
..0..1..0..0....1..0..0..0....0..1..0..1....0..0..0..0....1..0..0..0

Crossrefs

Sequence in context: A328809 A327603 A336540 * A370327 A104209 A121247

Adjacent sequences: A228746 A228747 A228748 * A228750 A228751 A228752

Keyword

nonn

Author

R. H. Hardin Sep 02 2013

Status

approved