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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. 0
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 (list; graph; refs; listen; history; text; internal format)
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 * A140352 A277130 A082588

Adjacent sequences:  A145966 A145967 A145968 * A145970 A145971 A145972

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 25 2008

STATUS

approved

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Last modified September 28 09:32 EDT 2021. Contains 347714 sequences. (Running on oeis4.)