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A066351 Bisection of A007059. 2
1, 2, 5, 14, 43, 140, 472, 1628, 5719, 20388, 73562, 268066, 984911, 3643570, 13557020, 50691978, 190353370, 717457656, 2713061899, 10289600164, 39127877886, 149147692734, 569767908076, 2180978471298, 8363866011929, 32129445138352, 123618810558184 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

R. Kemp, Balanced ordered trees, Random Structures and Algorithms, 5, 1994, 99-121.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..500

FORMULA

Conjecture: a(n) ~ 0.721... * 4^n / n. - Vaclav Kotesovec, Aug 25 2014

MAPLE

b:= proc(n, m) option remember; `if`(n=0, 1,

      `if`(m=0, add(b(n-j, j), j=1..n),

      add(b(n-j, min(n-j, m)), j=1..min(n, m))))

    end:

a:= n-> b(2*n, 0):

seq(a(n), n=0..40);  # Alois P. Heinz, May 13 2014

MATHEMATICA

b[n_, m_] := b[n, m] = If[n == 0, 1, If[m == 0, Sum[b[n - j, j], {j, 1, n} ], Sum[b[n - j, Min[n - j, m]], {j, 1, Min[n, m]}]]]; a[n_] := b[2*n, 0]; Table[a[n], {n, 0, 40}] (* Jean-Fran├žois Alcover, Dec 22 2016, after Alois P. Heinz *)

CROSSREFS

Sequence in context: A071755 A149879 A149880 * A181496 A276989 A272461

Adjacent sequences:  A066348 A066349 A066350 * A066352 A066353 A066354

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Dec 19 2001

EXTENSIONS

More terms from Emeric Deutsch, Jun 10 2004

STATUS

approved

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Last modified October 22 07:53 EDT 2021. Contains 348160 sequences. (Running on oeis4.)