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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A339525 Number of unordered pairs of rooted trees with a total of n nodes and an odd total of leaves. 2
 0, 0, 0, 1, 3, 8, 19, 47, 119, 309, 805, 2115, 5594, 14920, 40037, 108068, 293124, 798739, 2185380, 6001797, 16538728, 45716315, 126727586, 352214041, 981269274, 2739925455, 7666335708, 21491822234, 60358497108, 169798015580, 478420350367 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS Equivalently, the number of rooted trees on n+1 nodes, where the root has degree 2, and the number of leaves is odd. To get a pair of trees with an odd number of leaves one tree must have an even number of leaves and the other an odd number of leaves. LINKS Table of n, a(n) for n=1..31. Washington Bomfim, Illustration of initial terms Index entries for sequences related to rooted trees FORMULA a(n) = Sum_{k=1, n-1}( A253013(k) * A253014(n-k) ). CROSSREFS Cf. A253013, A253014, A339524. Sequence in context: A121811 A244208 A296329 * A295045 A181849 A164586 Adjacent sequences: A339522 A339523 A339524 * A339526 A339527 A339528 KEYWORD nonn AUTHOR Washington Bomfim, Dec 08 2020 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 December 1 13:31 EST 2023. Contains 367475 sequences. (Running on oeis4.)