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A286139
Number of connected induced (non-null) subgraphs of the n X n king graph.
18
1, 15, 388, 37196, 14765089, 24076152503, 159850328891568, 4290837646252661680, 463376724731585422732393, 200665409586497566263900755703, 347694350828123116321061347501951972, 2406781070555276417850396576804205226358828, 66481859567653621586313146932097075651519991887257
OFFSET
1,2
LINKS
Eric Weisstein's World of Mathematics, King Graph
Eric Weisstein's World of Mathematics, Vertex-Induced Subgraph
MATHEMATICA
Table[If[n<2, n, g = GraphData[{"King", {n, n}}]; -1 + ParallelSum[ Boole@ ConnectedGraphQ@ Subgraph[g, s], {s, Subsets@ Range[n^2]}]], {n, 4}]
CROSSREFS
Cf. A020873 (wheel), A059020 (ladder), A059525 (grid), A286182 (prism), A286183 (antiprism), A286184 (helm), A286185 (Möbius ladder), A286186 (friendship), A286187 (web), A286188 (gear), A286189 (rook), A285765 (queen).
Sequence in context: A164323 A374000 A129615 * A069990 A157581 A143001
KEYWORD
nonn,hard
AUTHOR
Giovanni Resta, May 03 2017
EXTENSIONS
a(10)-a(13) from Andrew Howroyd, May 20 2017
STATUS
approved