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Series of sorts- Return 1 or 2 based on even or odd n

  1. Mar 5, 2013 #1
    I would like to create a series where for each term if n is odd the term =1 and if n is even, the term = 2. I.e.

    [itex]a_{n} = 1 if \ n \ is \ odd \ and \ a_{n} = 2 \ if \ n \ is \ even[/itex]
  2. jcsd
  3. Mar 5, 2013 #2
    Can anyone help me come up with some a_n such that this is true?
  4. Mar 5, 2013 #3
    So what you are saying is ...

    For input n = 1,2,3,4,5...

    a_n = 1,2,1,2,1,2

    There are a number of ways you can do this (click on Equations for Links )...

    [itex]2- n mod(2)[/itex]

    [itex]2-[sin^2(\frac{\pi n}{2})][/itex]

    Just a couple that I thought off in my head....
    One is discrete, one is continuous
  5. Mar 5, 2013 #4


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    Science Advisor

    There is also ##\frac{3+(-1)^n}{2}##
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