|
|
A070862
|
|
Number of path covers of an n X n grid.
|
|
0
|
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
A path cover is set of disjoint paths such that each node of the graph belongs to exactly one of these. A Hamiltonian path is a special path cover consisting of a single path. Paths of length zero (i.e. single nodes) are permitted.
|
|
LINKS
|
|
|
EXAMPLE
|
a(1) = 1 as there is only the trivial cover by a single path of length 0
a(2) = 15 = 1 (all length 0) + 4 (2x0, 1x1) + 2 (2x1) + 4 (1x2, 1x0) + 4 (1x3)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Andre Poenitz (poenitz(AT)htwm.de), Nov 26 2003
|
|
STATUS
|
approved
|
|
|
|