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-   -   Help with maths sequence (https://www.askmehelpdesk.com/showthread.php?t=810146)

  • Apr 6, 2015, 03:25 AM
    Michellefrance6
    Help with maths sequence
    Hi.
    What's the following numbers in the sequence
    1-4-14-51-216-
    Many thanks.

    Michelle.
  • Apr 6, 2015, 03:37 AM
    Curlyben
    What do YOU think ?
    While we're happy to HELP we wont do all the work for you.
    Show us what you have done and where you are having problems..
  • Apr 6, 2015, 05:19 AM
    Michellefrance6
    Hi,OK - I've tried looking at the differences in the numbers so, between 1 and 4 there is a difference of 3, between 14 and for a difference of 10, 51 and 14 a difference of 37 and between 216 a difference of 165. I've then looked at the 2nd differences and the third differences and finally I end up with 81, so none of the differences are the same!I know that because of the big difference in numbers I will need to multiply. I've tried adding first and then multiplying and it works for the first two:eg. 1 x 3 +1 = 4 4 x 3 + 2 = 1414 x 3 + 3 = 47!! HELP!! Michelle
  • Apr 6, 2015, 05:51 AM
    ebaines
    Hint: play around with the idea that nth term is (n-1) times the (n-1)th term, plus a factor.
  • Apr 6, 2015, 08:19 AM
    Michellefrance6
    Hi,This is doing my brain in! I've tried that on the second and third numbers and it works but not on the others.((4-1) x 5) - 1 = 14((14-1) x 4) - 1 = 51 Michelle
  • Apr 6, 2015, 08:40 AM
    ebaines
    For n-2: 2nd number is equal to the first number times 1, plus ...what?

    For n=3: 3rd number is equal to the 2nd times 2, plus what?

    For n=4: the 4th number = 3rd number times 3, plus?

    etc.
  • Apr 6, 2015, 08:47 AM
    Michellefrance6
    Quote:

    Originally Posted by ebaines View Post
    For n-2: 2nd number is equal to the first number times 1, plus ...what?

    For n=3: 3rd number is equal to the 2nd times 2, plus what?

    For n=4: the 4th number = 3rd number times 3, plus?

    etc.


    OK - gottit. Thx.

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