A286139 Number of connected induced (non-null) subgraphs of the n X n king graph.

1, 15, 388, 37196, 14765089, 24076152503, 159850328891568, 4290837646252661680, 463376724731585422732393, 200665409586497566263900755703, 347694350828123116321061347501951972, 2406781070555276417850396576804205226358828, 66481859567653621586313146932097075651519991887257

Offset

1,2

Links

Andrew Howroyd, Table of n, a(n) for n = 1..16

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

Adjacent sequences: A286136 A286137 A286138 * A286140 A286141 A286142

Keyword

nonn,hard

Author

Giovanni Resta, May 03 2017

Extensions

a(10)-a(13) from Andrew Howroyd, May 20 2017

Status

approved