Maths problem

Discussion in 'Shooting the Breeze' started by cremeegg, Jan 5, 2018.

  1. cremeegg

    cremeegg Frequent Poster

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    Can anyone out there help me with this.

    I need to find the next number in the sequence below.

    It is a proper sequence, in that there is a rule to generate the next element. If I can find the rule, there maybe a considerable reward. It is part of a larger problem, but I think that if I can crack this part, I have the rest.

    1,2,5,7,12,15,22,35,40,57,70,77,92
     
  2. Dan Murray

    Dan Murray Frequent Poster

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    Hi Cremeegg,

    This has me foxed. I thought I had it cracked - as a generalised pentagonal number sequence as per the attached link:
    https://en.wikipedia.org/wiki/Pentagonal_number

    All the numbers mentioned above fall into this sequence - it's just that there should be additional numbers also. Ouch! :(
     
  3. cremeegg

    cremeegg Frequent Poster

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    Thats brilliant Dan, I some have further numbers in the sequence and I checked the first 33 generalised pentagonal numbers map the first 22 numbers of my sequence, with none missed.

    The previous system I was using produced 392 numbers to give me the first 22 numbers.

    The prize is simply for finding the next number, generating 3 or more and testing to find the correct one may not be pretty but I think it is acceptable. Of course a formula to generate the sequence and only the sequence would be ideal.
     
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  4. Dan Murray

    Dan Murray Frequent Poster

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    Last edited: Jan 6, 2018
    Happy that it may help! Now let's deal with the elephant in the room or, as some might put it, the moral issue here.

    What's my percentage?!:D

    Regarding the quote above, my gut tells me it's impossible - but I'm just after reading Thinking Fast and Slow and think I'll never be able to trust my gut again!!

    [Me writing the immediate above is good news for you - there are some smart buachaillí out there who would just love to demonstrate how unreliable my gut is!!]
     
    Last edited: Jan 6, 2018
  5. Purple

    Purple Frequent Poster

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    Great book.
     
  6. Dan Murray

    Dan Murray Frequent Poster

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    Indeed. The type of thinking deficits that he discusses can, on occasion, make appearances in these here parts - including by yours truly, not more than most, but occasionally nonetheless! :D
     
  7. cremeegg

    cremeegg Frequent Poster

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    I think it is fair to say that the Kudos from solving this would quieten those buachaillí or indeed Cailiní for a while.

    Speaking of whom, where has your friend the Duke gone.
     
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  8. Dan Murray

    Dan Murray Frequent Poster

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    I just don't know. He just said he wasn't going to engage with me anymore - unilaterally breaking off our engagement. If I'm totally honest, I think it had been coming for some time. Still, it's disappointing.