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A194093
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The number of labeled biconnected squaregraphs with n vertices.
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5
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1, 1, 0, 1, 0, 3, 0, 12, 2, 55, 22, 278, 182, 1506, 1378, 8595, 10040, 51134, 71814, 314693, 509200
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,6
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REFERENCES
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LINKS
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EXAMPLE
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[See A194089 for the definition of "labeling".] For n=11 the P-pentomino can be labeled in 20 ways; the 5-cogwheel 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.
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PROG
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(CWEB) (see Knuth link).
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CROSSREFS
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KEYWORD
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nonn,hard,more
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AUTHOR
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STATUS
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approved
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