A145794 Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only either four adjacent vertically or four adjacent horizontally.

1, 1, 1, 1, 1, 2, 1, 3, 2, 5, 6, 12, 20, 34, 68, 154, 265, 709, 1281, 3847, 8603, 25073, 71217, 206107, 695670, 2185029, 7989257, 27851353, 111404338, 424685942

Offset

1,6

Links

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

Crossrefs

Sequence in context: A102517 A062951 A263150 * A176741 A266138 A014000

Adjacent sequences: A145791 A145792 A145793 * A145795 A145796 A145797

Keyword

nonn

Author

R. H. Hardin, Oct 19 2008

Status

approved