This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A215859 Number of simple labeled graphs on n nodes with exactly 9 connected components that are trees or cycles. 3
 1, 45, 1650, 54945, 1795794, 59546487, 2043490735, 73415619420, 2779264615127, 111226656560877, 4710924208619304, 211105699482022215, 9997623229700175712, 499562336689773070263, 26288415481415803589236, 1454007169289989503463230, 84361156450441837460650255 (list; graph; refs; listen; history; text; internal format)
 OFFSET 9,2 LINKS Alois P. Heinz, Table of n, a(n) for n = 9..150 EXAMPLE a(10) = 45: each graph has one 2-node tree and 8 1-node trees and C(10,2) = 45. MAPLE T:= proc(n, k) option remember; `if`(k<0 or k>n, 0,       `if`(n=0, 1, add(binomial(n-1, i)*T(n-1-i, k-1)*       `if`(i<2, 1, i!/2 +(i+1)^(i-1)), i=0..n-k)))     end: a:= n-> T(n, 9): seq(a(n), n=9..25); CROSSREFS Column k=9 of A215861. The unlabeled version is A215989. Sequence in context: A014940 A273436 A049397 * A143170 A203828 A318221 Adjacent sequences:  A215856 A215857 A215858 * A215860 A215861 A215862 KEYWORD nonn AUTHOR Alois P. Heinz, Aug 26 2012 STATUS approved

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

Last modified June 17 22:17 EDT 2019. Contains 324200 sequences. (Running on oeis4.)