A145795 Number of n X n binary arrays symmetric under 90-degree rotation with all ones connected only either four adjacent vertically or four adjacent horizontally.

1, 1, 1, 1, 1, 4, 7, 15, 34, 91, 268, 848, 2982, 11440, 47890, 231566, 1214519, 7161065, 45785181, 328548555, 2571260385, 22573158713, 216461088819, 2326997861375, 27251383779874, 358326282799095

Offset

1,6

Links

Table of n, a(n) for n=1..26.

Crossrefs

Sequence in context: A201498 A145970 A232048 * A173657 A213358 A065935

Adjacent sequences: A145792 A145793 A145794 * A145796 A145797 A145798

Keyword

nonn

Author

R. H. Hardin, Oct 19 2008

Status

approved