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A236690
Number of simple directed paths on an n X n king graph.
2
1, 64, 10305, 12029640, 115066382913, 9913814758253424, 7908201732771623795865, 59973177127583169531861733624, 4374964523946648320195747609012311225, 3101392210136336400751621092299022481429113152
OFFSET
1,2
COMMENTS
This is the number (assuming each character is unique) of strings that are possible in an n X n Boggle grid.
This sequence gives the number of directed paths. Paths may start and end on any vertex and may be of any length. Paths of length zero are counted here. - Andrew Howroyd, May 12 2017
LINKS
Eric Weisstein's World of Mathematics, King Graph
FORMULA
a(n) = 2*A288033(n) + n^2. - Andrew Howroyd, Jun 10 2017
CROSSREFS
Cf. A236753 for a simpler version of the problem without diagonal edges.
Sequence in context: A220731 A239403 A254607 * A362541 A268055 A268078
KEYWORD
nonn,hard
AUTHOR
Jaimal Ichharam, Jan 30 2014
EXTENSIONS
a(5) from Jaimal Ichharam, Feb 12 2014
Named edited and a(6)-a(10) from Andrew Howroyd, May 12 2017
STATUS
approved