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A146156 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only either as two by three or three by two blocks. 0
1, 1, 1, 1, 1, 1, 2, 4, 7, 11, 20, 47, 126, 349, 1026, 3169, 10962, 42335, 178967, 817710, 4108982, 22332287, 134485764, 875416554, 6255533128, 48551931040, 415466055841, 3858971189964, 39521400790374, 437870905678969 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

LINKS

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

EXAMPLE

Maximal 8 X 8 example

.0.0.0.1.1.0.0.0

.0.0.0.1.1.0.0.0

.0.0.0.1.1.0.0.0

.1.1.1.0.0.1.1.1

.1.1.1.0.0.1.1.1

.0.0.0.1.1.0.0.0

.0.0.0.1.1.0.0.0

.0.0.0.1.1.0.0.0

CROSSREFS

Sequence in context: A160393 A018173 A288380 * A304916 A024927 A018077

Adjacent sequences:  A146153 A146154 A146155 * A146157 A146158 A146159

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 27 2008

STATUS

approved

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Last modified June 20 23:09 EDT 2021. Contains 345303 sequences. (Running on oeis4.)