Fibonacci Sequence (aka Fibonacci Series)

May 15, 2012

What is Fibonacci?

(Or, more appropriately, who was Fibonacci and what is the Fibonacci Sequence?)

 


Leonardo Fibonacci discovered the sequence which converges on phi

Leonardo Fibonacci, discoverer of the Fibonacci series which is related to phi, the Golden ProportionIn the 12th century, Leonardo Fibonacci discovered a simple numerical sequence that is the foundation for an incredible mathematical relationship behind phi.

Starting with 0 and 1, each new number in the sequence is simply the sum of the two before it.

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, . . .

The ratio of each successive pair of numbers in the sequence approximates phi (1.618. . .) , as 5 divided by 3 is 1.666…, and 8 divided by 5 is 1.60.

The table below shows how the ratios of the successive numbers in the Fibonacci sequence quickly converge on Phi.  After the 40th number in the sequence, the ratio is accurate to 15 decimal places.

1.618033988749895 . . .


Compute any number in the Fibonacci Sequence easily!

Here are two ways you can use phi to compute the nth number in the Fibonacci sequence (fn).

If you consider 0 in the Fibonacci sequence to correspond to n = 0, use this formula:

fn =  Phi n / 5½

Perhaps a better way is to consider 0 in the Fibonacci sequence to correspond to the 1st Fibonacci number where n = 1 for 0.  Then you can use this formula, discovered and contributed by Jordan Malachi Dant in April 2005:

fn =  Phi n / (Phi + 2)

Both approaches represent limits which always round to the correct Fibonacci number and approach the actual Fibonacci number as n increases.


The ratio of successive Fibonacci numbers converges on phi

Sequence
in the
sequence
Resulting
Fibonacci
number
(the sum
of the two
numbers
before it)
Ratio of each
number to the
one before it
(this estimates
phi)
Difference
from
Phi

0

0

1 1
2 1 1.000000000000000 +0.618033988749895
3 2 2.000000000000000 -0.381966011250105
4 3 1.500000000000000 +0.118033988749895
5 5 1.666666666666667 -0.048632677916772
6 8 1.600000000000000 +0.018033988749895
7 13 1.625000000000000 -0.006966011250105
8 21 1.615384615384615 +0.002649373365279
9 34 1.619047619047619 -0.001013630297724
10 55 1.617647058823529 +0.000386929926365
11 89 1.618181818181818 -0.000147829431923
12 144 1.617977528089888 +0.000056460660007
13 233 1.618055555555556 -0.000021566805661
14 377 1.618025751072961 +0.000008237676933
15 610 1.618037135278515 -0.000003146528620
16 987 1.618032786885246 +0.000001201864649
17 1,597 1.618034447821682 -0.000000459071787
18 2,584 1.618033813400125 +0.000000175349770
19 4,181 1.618034055727554 -0.000000066977659
20 6,765 1.618033963166707 +0.000000025583188
21 10,946 1.618033998521803 -0.000000009771909
22 17,711 1.618033985017358 +0.000000003732537
23 28,657 1.618033990175597 -0.000000001425702
24 46,368 1.618033988205325 +0.000000000544570
25 75,025 1.618033988957902 -0.000000000208007
26 121,393 1.618033988670443 +0.000000000079452
27 196,418 1.618033988780243 -0.000000000030348
28 317,811 1.618033988738303 +0.000000000011592
29 514,229 1.618033988754323 -0.000000000004428
30 832,040 1.618033988748204 +0.000000000001691
31 1,346,269 1.618033988750541 -0.000000000000646
32 2,178,309 1.618033988749648 +0.000000000000247
33 3,524,578 1.618033988749989 -0.000000000000094
34 5,702,887 1.618033988749859 +0.000000000000036
35 9,227,465 1.618033988749909 -0.000000000000014
36 14,930,352 1.618033988749890 +0.000000000000005
37 24,157,817 1.618033988749897 -0.000000000000002
38 39,088,169 1.618033988749894 +0.000000000000001
39 63,245,986 1.618033988749895 -0.000000000000000
40 102,334,155 1.618033988749895 +0.000000000000000

Tawfik Mohammed notes that 13, considered by some to be an unlucky number, is found at position number 7, the lucky number!

The Fibonacci Sequence and Gambling or Lotteries

Some people hope that Fibonacci numbers will provide an edge in picking lottery numbers or bets in gambling. The truth is that the outcomes of games of chance are determined by random outcomes and have no special connection to Fibonacci numbers.

Roulette tables can use the Fibonacci method of bettingThere are, however, betting systems used to manage the way bets are placed, and the Fibonacci system based on the Fibonacci sequence is a variation on the Martingale progression. In this system, often used for casino and online roulette, the pattern of bets placed follows a Fibonacci progression: i.e., each wager should be the sum of the previous two wagers until a win is made. If a number wins, the bet goes back two numbers in the sequence because their sum was equal to the previous bet.

In the Fibonacci system the bets stay lower then a Martingale Progression, which doubles up every time. The downside is that in the Fibonacci roulette system the bet does not cover all of the losses in a bad streak.

An important caution: Betting systems do not alter the fundamental odds of a game, which are always in favor of the casino or the lottery. They may just be useful in making the playing of bets more methodical, as illustrated in the example below:

Round Scenario 1 Scenario 2 Scenario 3
Bet 1 Bet 1 and lose Bet 1 and lose Bet 1 and win
Bet 2 Bet 1 and lose Bet 1 and lose Bet 1 and win
Bet 3 Bet 2 and win Bet 2 and lose Bet 1 and lose
Bet 4 - Bet 3 and win Bet 1 and lose
Bet 5 - - Bet 2 and win
Net Result Even at 0 Down by 1 Ahead by 2

 

 

 

 

 

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Leave a Comment

{ 13 comments… read them below or add one }

matthew C Culver June 11, 2012 at 9:06 pm

DANTS FORMULA IS THE LOG OF ONE DEFINED DIMENSION TO THE DIVISION OF ITSELF

Reply

matthew C Culver June 11, 2012 at 9:10 pm

FIBONACCI is the combinations of moves and or optimization
one must make inorder to complete a task, taking in scenarios
in which one would never lose.

Reply

John July 30, 2012 at 7:07 am

Thank you for your input and clarification sir. The original way is golden! You can never loose! Any other way can lead to a path of darkness and confusion as you try to come full circle.

Reply

Patrick September 12, 2012 at 8:45 pm

I love the column, but it hits something of a pet peeve. Check out
http://en.wikipedia.org/wiki/Series_(mathematics)
to see the distinction between a sequence and a series. Basically, everywhere you see the word “series”, it should be “sequence”. Instead of “Sequence in the series”, how about “Position in the sequence”.

Reply

Gary Meisner September 24, 2012 at 7:51 pm

Thank you for the insight on this. There seem to be differing definitions depending on the source. Dictionary.com defines series as “a group or a number of related or similar things, events, etc., arranged or occurring in temporal, spatial, or other order or succession; sequence” followed by “Series, sequence, succession are terms for an orderly following of things one after another. Series is applied to a number of things of the same kind, usually related to each other, arranged or happening in order: a series of baseball games. Sequence stresses the continuity in time, thought, cause and effect, etc.: The scenes came in a definite sequence. Succession implies that one thing is followed by another or others in turn, usually though not necessarily with a relation or connection between them: succession to a throne; a succession of calamities.” Google lists 1.2 million references for “Fibonacci Series” and 2.1 million references for “Fibonacci sequence” so both are in common usage, although sequence is apparentely more prevalent. I’ll review your suggested changes and include these comments to the post for clarification.

Reply

Lou Hawthorne March 28, 2013 at 3:11 pm

Gary – Very interesting article and table. FYI, Patrick is correct that series and sequence have specific meanings and are not interchangeable to mathematicians, not matter what Google or various dictionaries say. To mathematicians, a sequence is a progression of numbers generated by a function, whereas a series is the sum of numbers in a sequence. Your article is too good in other respects to use these terms in non-mathematical ways.
Best,
Lou

Reply

Gary Meisner March 29, 2013 at 10:24 pm

Thanks, Lou. I’ve taken your advice and changed the references in the article to sequence from series.

Reply

Shelley November 5, 2012 at 3:56 am

I am very curious about the “sequence” and how it affects us as people in our daily lives. John says it is the combinations of moves and or optimization one must make in order to complete a task, taking in scenarios in which one would never lose. Could you point me to more information how this connects with our lives, past, present and future? and if in laymen terms that would be even better.

Thanks for your kind consideration of my request.

Cheers Shelley

Reply

ben December 24, 2012 at 6:36 am

is the difference from phi column actually an inverted fibonacci series where you skip one number each time? 1+2=3, 2+3=5 but only 1,2 & 5 are in the sequence. next is 14, 36…

Reply

Janne January 9, 2013 at 4:36 am

Thank you …

Reply

Martin March 31, 2013 at 8:35 pm

How brilliant he must have been. And now we use calculators. Thanks — Martin

Reply

Mike E. April 5, 2013 at 11:49 am

Nor sure if you’ve seen the work done by artist Vi Hart posted on Kahn Academy. If not, enjoy. Love your site.

https://www.khanacademy.org/math/recreational-math/vi-hart

Reply

hardik May 13, 2013 at 8:31 am

awesome!!!!!!!!!!!!!!!!!!!!!!!!!!

Reply

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