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A318571 a(n) = ceiling(log(2)/(log(1+n/100))). 0
70, 36, 24, 18, 15, 12, 11, 10, 9, 8, 7, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) is the least positive integer k such that (1 + n/100)^k >= 2.

LINKS

Table of n, a(n) for n=1..100.

Wikipedia, Rule of 72

FORMULA

a(n) = 1 for n >= 100.

EXAMPLE

n | a(n) | Rule of 72 (= 72/n)

------+------+---------------------

1 | 70 | 72

2 | 36 | 36

3 | 24 | 24

4 | 18 | 18

5 | 15 | 14.4

6 | 12 | 12

7 | 11 | 10.285714...

8 | 10 | 9

9 | 9 | 8

10 | 8 | 7.2

11 | 7 | 6.545454...

12 | 7 | 6

MAPLE

seq(ceil(log(2)/(log(1+n/100))), n=1..100); # Muniru A Asiru, Aug 30 2018

MATHEMATICA

Table[Ceiling[Log[2]/Log[1 + n/100]], {n, 100}] (* Vincenzo Librandi, Sep 01 2018 *)

PROG

(PARI) {a(n) = ceil(log(2)/(log(1+n/100)))}

(Magma) [Ceiling(Log(2)/(Log(1+n/100))): n in [1..100]]; // Vincenzo Librandi, Sep 01 2018

CROSSREFS

Sequence in context: A361040 A033390 A129352 * A156810 A252714 A245046

Adjacent sequences: A318568 A318569 A318570 * A318572 A318573 A318574

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Aug 29 2018

STATUS

approved

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Last modified March 27 03:58 EDT 2023. Contains 361553 sequences. (Running on oeis4.)