The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A005173 Number of trees of subsets of an n-set. (Formerly M4844) 1
 0, 1, 12, 61, 240, 841, 2772, 8821, 27480, 84481, 257532, 780781, 2358720, 7108921, 21392292, 64307941, 193185960, 580082161, 1741295052, 5225982301, 15682141200, 47054812201, 141181213812, 423577195861, 1270798696440 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 REFERENCES F. R. McMorris and T. Zaslavsky, The number of cladistic characters, Math. Biosciences, 54 (1981), 3-10. N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Table of n, a(n) for n=1..25. F. R. McMorris and T. Zaslavsky, The number of cladistic characters, Math. Biosciences, 54 (1981), 3-10. [Annotated scanned copy] Simon Plouffe, Approximations de séries génératrices et quelques conjectures, Dissertation, Université du Québec à Montréal, 1992; arXiv:0911.4975 [math.NT], 2009. Simon Plouffe, 1031 Generating Functions, Appendix to Thesis, Montreal, 1992 Index entries for sequences related to trees Index entries for linear recurrences with constant coefficients, signature (6, -11, 6). FORMULA G.f.: x ( 1 + 6 x ) / ( 1 - x ) / ( 1 - 2 x ) / ( 1 - 3 x ). - corrected Ray Chandler, Jun 26 2023 First differences give A003063, 3^(n-1)-2^n. MAPLE A005173:=-z*(1+6*z)/(z-1)/(3*z-1)/(2*z-1); [Conjectured by Simon Plouffe in his 1992 dissertation.] MATHEMATICA CoefficientList[Series[x (1+6 x)/(1-x)/(1-2 x)/(1-3 x), {x, 0, 30}], x] (* Harvey P. Dale, Jul 03 2023 *) CROSSREFS Cf. A003063. Sequence in context: A240002 A114241 A127766 * A196144 A294682 A177677 Adjacent sequences: A005170 A005171 A005172 * A005174 A005175 A005176 KEYWORD nonn,easy AUTHOR N. J. A. Sloane. EXTENSIONS More terms from Larry Reeves (larryr(AT)acm.org), Feb 06 2001 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 23 06:23 EDT 2023. Contains 365533 sequences. (Running on oeis4.)