A145958 Number of n X n binary arrays symmetric under 90-degree rotation with all ones connected only in a zee 1,1 1,2 2,2 2,3 in any orientation.

1, 1, 1, 1, 1, 9, 19, 37, 135, 441, 1879, 9853, 53945, 336895, 2463469, 20551403, 200816385, 2276422523, 29317863291, 437152357559, 7466970790985, 147328291419831, 3346732661121193

Offset

1,6

Links

Table of n, a(n) for n=1..23.

Example

Maximal 8 X 8 example:
  0 1 0 0 0 1 1 0
  1 1 0 1 1 0 1 1
  1 0 1 0 1 1 0 0
  0 1 1 0 0 0 1 0
  0 1 0 0 0 1 1 0
  0 0 1 1 0 1 0 1
  1 1 0 1 1 0 1 1
  0 1 1 0 0 0 1 0

Crossrefs

Sequence in context: A157034 A198590 A297396 * A290245 A039299 A211114

Adjacent sequences: A145955 A145956 A145957 * A145959 A145960 A145961

Keyword

nonn

Author

R. H. Hardin, Oct 25 2008

Status

approved