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 A022562 Number of connected claw-free unlabeled graphs on n nodes. 24
 1, 1, 2, 5, 14, 50, 191, 881, 4494, 26389, 184749, 1728404, 23805256, 491544474, 14491876320 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS R. Faudree, E. Flandrin and Z. Ryjacek, Claw-free graphs - a survey, Discr. Math., 164 (1997), 87-147. F. Hüffner, tinygraph, software for generating integer sequences based on graph properties, version 8489dde. Gordon Royle, 1728404 distinct 12-vertex connected clawfree graphs Gordon Royle, g6 format Eric Weisstein's World of Mathematics, Claw-Free Graph Wikipedia, Claw-free Graph FORMULA Inverse Euler transform of A086991. - Andrew Howroyd, Nov 03 2017 MATHEMATICA EulerInvTransform[seq_] := Module[{final = {}}, For[i = 1, i <= Length[seq], i++, AppendTo[final, i*seq[[i]] - Sum[final[[d]]*seq[[i - d]], {d, i - 1}]]]; Table[Sum[MoebiusMu[i/d]*final[[d]], {d, Divisors[i]}]/i, {i, Length[seq]}]]; A086991 = Cases[Import["https://oeis.org/A086991/b086991.txt", "Table"], {_, _}][[All, 2]]; EulerInvTransform[A086991] (* Jean-François Alcover, Aug 20 2019, code due to Gus Wiseman *) CROSSREFS Cf. A022563, A022564, A058929, A086991 (Euler transform). Sequence in context: A224978 A006390 A100597 * A320954 A322725 A245883 Adjacent sequences:  A022559 A022560 A022561 * A022563 A022564 A022565 KEYWORD nonn,nice,more AUTHOR EXTENSIONS Corrected and extended by Gordon F. Royle, May 16 2003 Term a(14) added by Gordon F. Royle, Aug 06 2008 Term a(15) added using tinygraph by Falk Hüffner, Jan 12 2016 STATUS approved

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Last modified November 29 17:53 EST 2020. Contains 338769 sequences. (Running on oeis4.)