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A146056 Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 2X3 U in any orientation. 0
1, 1, 1, 1, 5, 1, 21, 9, 145, 29, 1925, 153, 28297, 2069, 734141, 42313, 33360929, 973281, 2205341673, 38746505, 212529048997, 2736250609, 33748456381053, 283141781389, 8526059147670681, 43072398238613, 3258206098233834291 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

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

EXAMPLE

Maximal 8 X 8 example

.0.0.0.0.0.0.0.0

.1.0.1.0.0.1.0.1

.1.1.1.0.0.1.1.1

.0.0.0.0.0.0.0.0

.0.0.0.0.0.0.0.0

.1.1.1.0.0.1.1.1

.1.0.1.0.0.1.0.1

.0.0.0.0.0.0.0.0

CROSSREFS

Sequence in context: A278544 A095368 A029757 * A101625 A051929 A347487

Adjacent sequences:  A146053 A146054 A146055 * A146057 A146058 A146059

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 26 2008

STATUS

approved

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Last modified September 27 08:39 EDT 2021. Contains 347689 sequences. (Running on oeis4.)