OFFSET
1,6
REFERENCES
See A194088
LINKS
Don Knuth, squaregraph.w (CWEB program).
EXAMPLE
[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.
PROG
(CWEB) (see Knuth link).
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Don Knuth, Aug 15 2011
STATUS
approved