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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: A201097 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 December 15 11:43 EST 2019. Contains 329999 sequences. (Running on oeis4.)