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A146020 Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only in a 2 X 4 el 1,1 1,2 1,3 1,4 2,4 with any orientation. 0
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 13, 13, 41, 41, 219, 219, 1033, 1033, 8217, 8217, 92671, 92671, 1241193, 1241193, 21102313 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,11

LINKS

Table of n, a(n) for n=1..27.

EXAMPLE

Maximal 11 X 11 example:

  0 0 0 1 1 0 1 1 0 0 0

  0 0 0 0 1 0 1 0 0 0 0

  0 0 0 0 1 0 1 0 0 0 0

  1 0 0 0 1 0 1 0 0 0 1

  1 1 1 1 0 0 0 1 1 1 1

  0 0 0 0 0 0 0 0 0 0 0

  1 1 1 1 0 0 0 1 1 1 1

  1 0 0 0 1 0 1 0 0 0 1

  0 0 0 0 1 0 1 0 0 0 0

  0 0 0 0 1 0 1 0 0 0 0

  0 0 0 1 1 0 1 1 0 0 0

CROSSREFS

Sequence in context: A146426 A146051 A146229 * A145948 A049768 A209390

Adjacent sequences:  A146017 A146018 A146019 * A146021 A146022 A146023

KEYWORD

nonn,more

AUTHOR

R. H. Hardin, Oct 26 2008

STATUS

approved

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Last modified October 18 23:44 EDT 2021. Contains 348071 sequences. (Running on oeis4.)