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A145762 Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only either three adjacent vertically or three adjacent horizontally. 0
1, 1, 1, 1, 2, 1, 4, 1, 11, 3, 36, 8, 178, 27, 1006, 96, 7478, 569, 70926, 4093, 898687, 37611, 14257237, 421080, 292647869, 6366190, 7706237478, 123605120, 263373760591, 3088656877 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

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

CROSSREFS

Sequence in context: A243913 A186724 A145930 * A024539 A128271 A092891

Adjacent sequences:  A145759 A145760 A145761 * A145763 A145764 A145765

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 17 2008

STATUS

approved

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Last modified February 16 15:17 EST 2020. Contains 331961 sequences. (Running on oeis4.)