A145780 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only either two adjacent vertically or two adjacent horizontally.

1, 1, 5, 18, 70, 523, 4956, 70926, 1300201, 37116376, 1354115636, 76887328413, 5596162598050, 631149201335604, 91196507989935319, 20473605176808584691, 5885534752273786907540, 2626715298620574785397735

Offset

1,3

Links

Table of n, a(n) for n=1..18.

Crossrefs

Sequence in context: A343490 A302077 A322773 * A183443 A034551 A052926

Adjacent sequences: A145777 A145778 A145779 * A145781 A145782 A145783

Keyword

nonn

Author

R. H. Hardin, Oct 18 2008

Status

approved