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A145946 Number of n X n binary arrays symmetric about main diagonal with all ones connected in a 3X2 elbow 1,1 1,2 1,3 2,3 in any orientation. 0
1, 1, 1, 3, 13, 41, 227, 1869, 21295, 308993, 6084845, 167200773, 6380227531, 331792369009, 23397509975499, 2257639231682789, 299410947515153649, 54437613856802551915, 13525155332080202787543, 4594219425445605883554215 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..20.

EXAMPLE

Maximal 8 X 8 example

.0.0.1.1.0.1.1.1

.0.0.0.1.0.0.0.1

.1.0.0.1.0.1.1.0

.1.1.1.0.0.1.0.1

.0.0.0.0.0.1.0.1

.1.0.1.1.1.0.1.1

.1.0.1.0.0.1.0.0

.1.1.0.1.1.1.0.0

CROSSREFS

Sequence in context: A173867 A121162 A146018 * A109224 A106050 A074425

Adjacent sequences:  A145943 A145944 A145945 * A145947 A145948 A145949

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 25 2008

STATUS

approved

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Last modified October 20 22:22 EDT 2021. Contains 348119 sequences. (Running on oeis4.)