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 A286187 Number of connected induced (non-null) subgraphs of the web graph with 3n nodes. 15
 6, 33, 188, 985, 4990, 24645, 119712, 574225, 2727218, 12847821, 60115060, 279652793, 1294441894, 5965567125, 27387631368, 125308264225, 571591760602, 2600204421405, 11799376912220, 53424388364873, 241398575303374, 1088727972172389, 4901842528232304, 22034981672761649 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Andrew Howroyd, Table of n, a(n) for n = 1..200 Eric Weisstein's World of Mathematics, Vertex-Induced Subgraph Eric Weisstein's World of Mathematics, Web Graph FORMULA Empirical g.f.: x*(6 - 39*x + 92*x^2 - 101*x^3 + 32*x^4 - 8*x^5 + 64*x^6 - 48*x^7) / ((1 - x)^2*(1 - 5*x + 2*x^2 + 4*x^3)^2). - Colin Barker, May 21 2017 MATHEMATICA {6, 33} ~Join~ Table[g = GraphData[{"Web", n}]; -1 + ParallelSum[Boole@ ConnectedGraphQ@ Subgraph[g, s], {s, Subsets@ Range[3 n]}], {n, 3, 6}] CROSSREFS Cf. A020873 (wheel), A059020 (ladder), A059525 (grid), A286139 (king), A286182 (prism), A286183 (antiprism), A286184 (helm), A286185 (Möbius ladder), A286186 (friendship), A286188 (gear), A286189 (rook), A285765 (queen). Sequence in context: A297221 A006630 A180035 * A260774 A218182 A093964 Adjacent sequences:  A286184 A286185 A286186 * A286188 A286189 A286190 KEYWORD nonn AUTHOR Giovanni Resta, May 04 2017 EXTENSIONS a(12)-a(24) from Andrew Howroyd, May 20 2017 STATUS approved

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Last modified May 29 07:49 EDT 2022. Contains 354122 sequences. (Running on oeis4.)