Generating Function for 0,1 Sequences with Period m

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Discussion Overview

The discussion revolves around generating functions for sequences of 0s and 1s with a specified period m. Participants explore different forms of these sequences and seek a general generating function that can accommodate various patterns based on the period.

Discussion Character

  • Exploratory
  • Mathematical reasoning

Main Points Raised

  • One participant asks for the generating function of sequences like 0,1,0,1 and others, specifying that m represents the period.
  • Another participant suggests looking up the sequences on the OEIS website for known generating functions.
  • Several participants propose that the generating function can be expressed as f(x)=1+x^2+x^4+x^6+..., relating it to another function g(x) that sums powers of x.
  • One participant indicates that the same approach applies to other sequences, providing a method to derive f(x) from g(x).
  • A later reply expresses enthusiasm for learning about generating functions and mentions a book recommendation for further exploration of the topic.
  • Another participant requests a proof related to a specific sequence format involving a summation and a fraction.

Areas of Agreement / Disagreement

Participants generally agree on the approach to derive generating functions for the sequences discussed, but there is no consensus on the final forms or proofs for all cases presented.

Contextual Notes

Some mathematical steps and assumptions regarding the sequences and their generating functions remain unresolved, and the discussion does not clarify all conditions under which the proposed functions hold.

Emilijo
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What is generating function of these sequences:
0,1,0,1...or
0,1,1,0,1,1,0...or
0,1,1,1,0,1,1,1,0...

where m is period, in first example m=2; in the second m=3, and so on.
Generating function must be general, so I can just put m.
 
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look up your sequences here:

https://oeis.org/

if they are known, they will be listed.
 
I am not satisfied. Can anyone answer on my question?
 
So you need to find a function such that

[tex]f(x)=1+x^2+x^4+x^6+x^8+...[/tex]

Do you know the function g such that

[tex]g(x)=1+x+x^2+x^3+x^4+x^5+...[/tex]

Then [itex]f(x)=g(x^2)[/itex]...
 
micromass said:
So you need to find a function such that

[tex]f(x)=1+x^2+x^4+x^6+x^8+...[/tex]

Do you know the function g such that

[tex]g(x)=1+x+x^2+x^3+x^4+x^5+...[/tex]

Then [itex]f(x)=g(x^2)[/itex]...
The other ones should be the same way, right? Like

[tex]f(x) = x + x^2 + x^4 + x^5 + x^7 + x^8 + ... = <br /> (1 + x + x^2 + x^3 + x^4 + ... ) - (1 + x^3 + x^6 + x^9 + ...) = <br /> g(x) - g(x^3)[/tex]
 
Indeed! That how I'd do the other ones!
 
micromass said:
Indeed! That how I'd do the other ones!

You're a great mentor! I had never heard of generating functions until I came to this post, but your post got me curious to go find the mechanics around that.

Learning a new thing every day. Thank you! :D
 
fbs7 said:
You're a great mentor! I had never heard of generating functions until I came to this post, but your post got me curious to go find the mechanics around that.

Learning a new thing every day. Thank you! :D

If you're really interested then I can recommend the book "Concrete Mathematics" by Knuth. The book gives several mathematical tools to solve problems that sound easy but whose solutions are far from it! Generating functions is one of those tools.
 
wee ned a proof for[tex]\overbrace{\,0,\,1,...\,1}^m\quad\frac{\sum_{i=1}^{m-1}x^i}{1\,-\,x^m}[/tex]
 

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