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A052326 Number of asymmetric trees with a forbidden limb of length 3. 1
1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 6, 11, 25, 49, 105, 211, 444, 903, 1880, 3865, 8042, 16658, 34764, 72484, 151856, 318418, 669934, 1411637, 2982407, 6311760, 13387127, 28442458, 60543586, 129084965, 275683061, 589660911, 1263128375 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,13

COMMENTS

A tree with a forbidden limb of length k is a tree where the path from any leaf inward hits a branching node or another leaf within k steps.

LINKS

Vaclav Kotesovec, Table of n, a(n) for n = 0..1000

Index entries for sequences related to Lyndon words

FORMULA

G.f.: 1 + B(x) + x^4 + x^5 + x^6 - (B(x^2) + B(x)^2)/2 where B(x) is g.f. of A052325.

a(n) ~ c * d^n / n^(5/2), where d = 2.2767145838879762709809174486..., c = 0.15900430026983804503695298... . - Vaclav Kotesovec, Aug 25 2014

CROSSREFS

Cf. A002955, A002988-A002992, A052318-A052329.

Sequence in context: A072986 A079047 A160966 * A079118 A211054 A034466

Adjacent sequences:  A052323 A052324 A052325 * A052327 A052328 A052329

KEYWORD

nonn

AUTHOR

Christian G. Bower, Dec 15 1999

EXTENSIONS

More terms, formula and comments from Christian G. Bower, Dec 15 1999

Typo in cross-reference corrected by Vaclav Kotesovec, Aug 25 2014

STATUS

approved

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Last modified April 20 22:22 EDT 2019. Contains 322310 sequences. (Running on oeis4.)