Fibonacci Series is the sequence of number, in which each number is the sum of previous two numbers.
   Example:- 0,1,1,2,3,5,8,13,21,34,55 .......... ∞
In Mathematics Fibonacci number is commonly denoted by F_n.
Thus, the Fibonacci sequence is,

n =	0	1	2	3	4	5	6	7	...	∞
Fn=	0	1	1	2	3	5	8	13	...	∞

In some cases, the value of F₀ = 0 is omitted.
So, that the sequence starts with F₁ = F ₂ =1,
and the recurrence is:
    F_n = F_{n - 1} + F_{n - 2} , is valid for n > 2.
Fibonacci Series and Golden ratio is closely related.

In Mathematics, a ratio of two quantities, where their ratio is the same as the ratio of their sum to the larger of two quantities is called Golden ratio.
denoted by Phi,. whose value is = 1.6180 .
The figure expressed algebraically, For quantities a, and b with a > b > 0.
More About Golden ratio: Golden ratio is really golden in words and in truths. Because the golden ratio is found everywhere, we can see it in Nature, it is found in sea shell, flowers, plants, human body, galaxies etc.
Golden ratio, whose value is = 1.6180 .
which can be obtained by taking any 2 successive fibonacci numbers, whose ratio is very close to the golden ratio. Bigger the pair of fibonacci numbers, closer is the approximation.
If one ask, what is the common among all the circles of the universe ? whether its a circumference of a thin hair or the circumference of the sun. The answer is simple and that is value of Pi = 3.14159...
Which is the ratio of circumference and diameter of a circle. Now, if one ask what is the common in entire creation ? Here also, the answer is simple but more interesting.
Mathematically, it is the golden ratio = 1.6180 .
Which is common in entire creation. Which is obtained by any 2 successive fibonacci number. Whose ratio corresponds to Golden ratio. When we see wide range of animate and inanimate objects in nature, ranging from a tiny atom to the gigantic galaxies and universe. They co-relates and corresponds to fibbonacci numbers and golden ratio. When a unit square is made adjacent to each other based on fibonacci sequence, It forms a wonderful fibonaci spiral, which is the direct evidence found, when analysing the pattern of seeds on a sunflower, galaxies,flowers etc.

A man named "Fibonacci", also known as Leonardo Pisano Bongollo. who lived in Italy between 1170 A.D. and 1250 A.D. "Fibonacci" was his nick name, which roughly means
" son of Bonacci". He was one of the most influential mathematicians of the middle ages.

November 23 ^rd, is declared as Fibonacci Day in honor of Leonardo Bonacci. The date corresponds to the first number of fibonacci sequence:- 1 1 2 3.