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A147174 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1000-1111-0010-0010 pattern in any orientation. 0
1, 1, 1, 1, 1, 1, 1, 1, 3, 9, 19, 35, 81, 217, 621, 1903, 7803, 32967, 151167, 704477, 3742519, 21530169 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,9

LINKS

Table of n, a(n) for n=1..22.

EXAMPLE

Maximal 9 X 9 example

.0.0.0.0.0.0.1.0.0

.0.0.0.1.1.1.1.0.0

.0.0.0.0.1.0.0.1.1

.0.1.0.0.1.0.0.1.0

.0.1.1.1.0.1.1.1.0

.0.1.0.0.1.0.0.1.0

.1.1.0.0.1.0.0.0.0

.0.0.1.1.1.1.0.0.0

.0.0.1.0.0.0.0.0.0

CROSSREFS

Sequence in context: A058058 A062748 A325666 * A147158 A014540 A293058

Adjacent sequences:  A147171 A147172 A147173 * A147175 A147176 A147177

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved

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Last modified September 21 12:35 EDT 2019. Contains 327253 sequences. (Running on oeis4.)