That's why I'm asking.Decoding Number Sequences: 17 or 27?

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Discussion Overview

The discussion revolves around the next number in a specific number sequence: 1, 3, 7, 11, 13. Participants are debating whether the next number is 17 or 27, with references to different patterns and interpretations of the sequence.

Discussion Character

  • Debate/contested
  • Exploratory
  • Mathematical reasoning

Main Points Raised

  • One participant suggests that the pattern of the sequence is +2, +4, +4, leading to the conclusion that the next number is 17.
  • Another participant questions the assumption that the pattern continues indefinitely, stating that without that assumption, there is no single correct answer.
  • Some participants propose that the next number could be 0, indicating a different interpretation of the sequence.
  • A participant introduces a more complex sequence that begins similarly but diverges, suggesting that the original sequence could be arbitrary and not uniquely defined.
  • Another participant mentions a reference to prime numbers and a specific sequence, asserting that there are many integer sequences that could fit the initial numbers provided.
  • There is a claim that the next number could be 27 if the sequence is related to Fibonacci numbers, although this connection is challenged by others who argue that the given numbers do not indicate a Fibonacci sequence.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the next number in the sequence, with multiple competing views remaining regarding the correct answer and the nature of the sequence itself.

Contextual Notes

The discussion highlights the ambiguity in defining the sequence and the assumptions made about its continuation. There are unresolved mathematical interpretations and differing perspectives on the nature of the sequence.

exodian
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Hello all,

I was wondering if you all could help me with a small problem.

Me and a friend had a discussion about a number sequence i found on http://www.fibonicci.com/en/number-sequences

1, 3, 7, 11, 13 ...

He says the next correct number is 27 and I say it's 17.

This forum seems full of very intelligent people, so i thought i post it here to get a definite answer! So which is the only correct one? :)
 
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it is +2 +4 +4 so the next number is 17.
 
Ye, i kno! :D but he goes mumbeling something about primenumbers 10+n^2 don't really understand it and says the next number is 27

Is this correct or not?

So if all of you people say its 17 then i win hehe ^^
 
The underlying assumption is that the current pattern continues indefinitely - you are assuming that the "+2 +4 + 4 +2 +4 +4" will go on forever. if you can make that assumption, then the answer would be 17. If you can't make that assumption, there is no single "correct" answer.
 
The next number is 0. They obviously meant the sequence
1, 3, 7, 11, 13, 0, 0, 0, 0, 0, 0, ...
 
Hurkyl said:
The next number is 0. They obviously meant the sequence
1, 3, 7, 11, 13, 0, 0, 0, 0, 0, 0, ...

What kind of sequence is this?
 
An arbitrary one.
 
A slightly less arbitrary sequence beginning this way is:
1, 3, 7, 11, 13, 17, 31, 33, 37, 71, 73, 77, 111, 113, 117, ...

Which is the sequence of numbers in base three with digits 1, 3, and 7 used instead of 0, 1, and 2.

"Guess which sequence I'm thinking of"-type questions are lame because no finite number of initial members will uniquely specify it.
 
exodian said:
but he goes mumbeling something about primenumbers 10+n^2 don't really understand it and says the next number is 27

Is this correct or not?

So if all of you people say its 17 then i win hehe ^^

Your friend refers to http://www.research.att.com/~njas/sequences/A114273 .

There is no single 'correct' answer. There are uncountably many integer sequences that start 1, 3, 7, 11, 13.
 
Last edited by a moderator:
  • #10
Yes, but he is talking about the fibbonacci numbers, in which case the next answer would be 27.
 
  • #11
Riogho said:
Yes, but he is talking about the fibbonacci numbers, in which case the next answer would be 27.

But nothing about the numbers he gave shows that it *is* the fibonacci sequence.
 

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