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A194093 The number of labeled biconnected squaregraphs with n vertices. 5


%S 1,1,0,1,0,3,0,12,2,55,22,278,182,1506,1378,8595,10040,51134,71814,

%T 314693,509200

%N The number of labeled biconnected squaregraphs with n vertices.

%D See A194088

%H Don Knuth, <a href="http://www-cs-faculty.stanford.edu/~knuth/programs/squaregraph.w">squaregraph.w</a> (CWEB program).

%e [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.

%e The values of a(1) and a(2) depend on whether or not one believes that

%e the small complete graphs K_1 and K_2 respectively are biconnected.

%o (CWEB) (see Knuth link).

%Y Cf. A194088, A194089, A194090, A194091, A194092.

%K nonn,hard,more

%O 1,6

%A _Don Knuth_, Aug 15 2011

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Last modified August 1 03:52 EDT 2021. Contains 346384 sequences. (Running on oeis4.)