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Math Help - Finding expressions for 4, 8, 32 ???

  1. #1
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    Finding expressions for 4, 8, 32 ???

    Finding expressions for sequences
    example: 2,4, 8, 16, 32 ...is 2^n
    where n= rank
    example: 3, 9, 27, 81 ...is 3^n

    soo what is the expression for 4, 8, 32
    you can express it in form of 2 to a certain power
    such that it is: 2^2 , 2^3, 2^5
    i tried 2^2n-1, it works for the 2nd and 3rd value but not the 1st ???

    OR it can be noticed that the powers are prime numbers
    so is the expression 2^p(n)

    ANY ideas????
    thnxx in advance
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  2. #2
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    Yes, it seems that it is 2^nth prime.
    2^2=4
    2^3=8
    2^5=32

    Therefore the next would be 2^7=128, 2^11=2048...
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  3. #3
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    Quote Originally Posted by GoneCrazy View Post
    Finding expressions for sequences
    ...

    soo what is the expression for 4, 8, 32
    you can express it in form of 2 to a certain power
    such that it is: 2^2 , 2^3, 2^5
    i tried 2^2n-1, it works for the 2nd and 3rd value but not the 1st ???

    OR it can be noticed that the powers are prime numbers
    so is the expression 2^p(n)

    ANY ideas????
    thnxx in advance
    I'm guessing only:

    How about

    2^2, 2^3, 2^{2+3}, 2^{3+5}, 2^{5+8}, ...
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