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A146041 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 2X4 tee 1,1 1,2 1,3 2,3 1,4 in any orientation. 0
1, 1, 1, 1, 5, 21, 83, 385, 2131, 24025, 318135, 5078109, 98561015, 2403657061, 86079554793, 4029871316637, 240018399697859, 18147620162041911, 1762019890516576641, 229246937643264356069, 39291648711744977550585 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..21.

EXAMPLE

Maximal 8 X 8 example

.0.1.1.1.1.0.0.0

.1.0.1.0.0.0.0.0

.1.1.0.1.1.1.1.0

.1.0.1.0.1.0.0.1

.1.0.1.1.0.0.0.1

.0.0.1.0.0.0.1.1

.0.0.1.0.0.1.0.1

.0.0.0.1.1.1.1.0

CROSSREFS

Sequence in context: A026017 A132310 A083319 * A146585 A215008 A026027

Adjacent sequences:  A146038 A146039 A146040 * A146042 A146043 A146044

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 26 2008

STATUS

approved

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Last modified September 24 14:46 EDT 2020. Contains 337321 sequences. (Running on oeis4.)