A145969 Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only in a 1 X 5 or 5 X 1 block.

1, 1, 1, 1, 1, 1, 2, 1, 3, 1, 6, 1, 15, 3, 43, 8, 140, 27, 656, 89, 3196, 333, 18641, 1310, 125685, 7293, 1010276, 48975, 9527791, 401989

Offset

1,7

Links

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

Example

Maximal 9 X 9 example:
  0 0 0 0 0 0 0 0 0
  0 0 1 1 1 1 1 0 0
  0 1 0 0 0 0 0 1 0
  0 1 0 0 0 0 0 1 0
  0 1 0 0 0 0 0 1 0
  0 1 0 0 0 0 0 1 0
  0 1 0 0 0 0 0 1 0
  0 0 1 1 1 1 1 0 0
  0 0 0 0 0 0 0 0 0

Crossrefs

Sequence in context: A034850 A220377 A329696 * A357985 A140352 A277130

Adjacent sequences: A145966 A145967 A145968 * A145970 A145971 A145972

Keyword

nonn

Author

R. H. Hardin, Oct 25 2008

Status

approved