

A194093


The number of labeled biconnected squaregraphs with n vertices.


5



1, 1, 0, 1, 0, 3, 0, 12, 2, 55, 22, 278, 182, 1506, 1378, 8595, 10040, 51134, 71814, 314693, 509200
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OFFSET

1,6


REFERENCES

See A194088


LINKS

Table of n, a(n) for n=1..21.
Don Knuth, squaregraph.w (CWEB program).


EXAMPLE

[See A194089 for the definition of "labeling".] For n=11 the Ppentomino can be labeled in 20 ways; the 5cogwheel in only 2; hence a(11)=22.
The values of a(1) and a(2) depend on whether or not one believes that
the small complete graphs K_1 and K_2 respectively are biconnected.


PROG

(CWEB) (see Knuth link).


CROSSREFS

Cf. A194088, A194089, A194090, A194091, A194092.
Sequence in context: A028851 A132221 A140093 * A055314 A110890 A249010
Adjacent sequences: A194090 A194091 A194092 * A194094 A194095 A194096


KEYWORD

nonn,hard,more


AUTHOR

Don Knuth, Aug 15 2011


STATUS

approved



