I Is the Series 2,3,5,8,13,21 a Fibonacci Sequence?

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The series 2, 3, 5, 8, 13, 21 can be considered a Fibonacci sequence if the definition allows for any two initial terms, as it follows the recursive formula F(n+1) = F(n) + F(n-1). Traditional definitions of Fibonacci sequences typically start with 0,1 or 1,1, leading to ambiguity in classification. The discussion highlights that the classification of a sequence as Fibonacci is dependent on the initial values chosen. Generalized Fibonacci sequences can be defined with different starting points, which should be explicitly stated. Ultimately, whether 2, 3, 5, 8, 13, 21 is a Fibonacci sequence depends on the context and definitions used.
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Is the series of numbers 2,3,5,8,13,21 ... a fibronacci sequence ? Because it doesn't start with 1 , but it fulfills the explicit formula .
 
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Ling Min Hao said:
Is the series of numbers 2,3,5,8,13,21 ... a fibronacci sequence ? Because it doesn't start with 1 , but it fulfills the explicit formula .
How do you define a Fibonacci sequence?
 
PeroK said:
How do you define a Fibonacci sequence?
I don't know , but from wikipedia , it says Fibronacci starts from either 0,1 or 1,1 but is 2,3,5,8,13,21... a Fibronacci sequence it remains unknown for me ..
 
Ling Min Hao said:
I don't know , but from wikipedia , it says Fibonacci starts from either 0,1 or 1,1 but is 2,3,5,8,13,21... a Fibronacci sequence it remains unknown for me ..
I guess it depends on author and purpose whether only the classical sequence is meant or all possible. I looked up "generalized Fibonacci sequence" and found, e.g. http://www.maths.surrey.ac.uk/hosted-sites/R.Knott/Fibonacci/fibGen.html

As so often the key lies in the question: What's your goal? Usually "a Fibonacci sequence" simply has to obey ##F_{n+1} = F_n + F_{n-1}##. Initial values result in different sequences. If someone speaks about "the Fibonacci sequence ##F_n##" he probably means the one starting with ##(0,1)##. Generalized ones should clearly by stated as such, which often can be recognized the way they define the initial values: ##(F_0,F_1)=(a_0,a_1)## indicates the usage of generalized ones. Formulas which contain ##F_n## without any further explanation probably refer to the classic sequence only.
 
Ling Min Hao said:
I don't know , but from wikipedia , it says Fibronacci starts from either 0,1 or 1,1 but is 2,3,5,8,13,21... a Fibronacci sequence it remains unknown for me ..
A question like this is entirely definition dependent. If you allow a Fibonacci sequence to have any two initial terms, then it is. If not, then it's not. Or, in this case, it is simply not the full sequence.
 
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If you apply prime numbers than it can be consider as a Fibonacci series. If you have any doubts to calculate Fibonacci series than you can visit Ashbox to use calculation tools.
 
Seemingly by some mathematical coincidence, a hexagon of sides 2,2,7,7, 11, and 11 can be inscribed in a circle of radius 7. The other day I saw a math problem on line, which they said came from a Polish Olympiad, where you compute the length x of the 3rd side which is the same as the radius, so that the sides of length 2,x, and 11 are inscribed on the arc of a semi-circle. The law of cosines applied twice gives the answer for x of exactly 7, but the arithmetic is so complex that the...
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