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A081288 a(n) is the minimal i such that A000108(i) > n. 9
0, 2, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Apart from the initial term 0, each n occurs A000245(n-1) times.

LINKS

Table of n, a(n) for n=0..100.

PROG

(Python)

from sympy import catalan

def a(n):

    if n==0: return 0

    i=1

    while True:

        if catalan(i)>n: return i

        else: i+=1

print [a(n) for n in range(0, 101)] # Indranil Ghosh, Jun 08 2017

(PARI) A081288(n) = my(i=0); while(binomial(2*i, i)/(i+1) <= n, i++); i; \\ Michel Marcus, Apr 28 2020

CROSSREFS

Cf. A072643, A081289, A081290. Used to compute A081291.

Sequence in context: A130193 A084516 A084526 * A130256 A335741 A103586

Adjacent sequences:  A081285 A081286 A081287 * A081289 A081290 A081291

KEYWORD

nonn

AUTHOR

Antti Karttunen, Mar 17 2003

STATUS

approved

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Last modified September 23 03:35 EDT 2020. Contains 337291 sequences. (Running on oeis4.)