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A145857 Number of n X n binary arrays with all ones connected only in two by two blocks. 1
1, 2, 5, 12, 72, 513, 4531, 68662, 1429824, 40840428, 1747979822, 106711196102, 9237029528023, 1158315077977449, 208422835867809541, 53674442198900292691, 19878424340459715152560, 10569643478952360023168707 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..18.

EXAMPLE

Maximal 7 X 7 example

.0.0.0.1.1.0.0

.1.1.0.1.1.0.0

.1.1.0.0.0.1.1

.0.0.1.1.0.1.1

.0.0.1.1.0.0.0

.1.1.0.0.0.1.1

.1.1.0.0.0.1.1

CROSSREFS

Sequence in context: A002358 A083699 A064636 * A197706 A205082 A060807

Adjacent sequences:  A145854 A145855 A145856 * A145858 A145859 A145860

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 22 2008

STATUS

approved

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Last modified June 18 03:02 EDT 2013. Contains 226328 sequences.