What comes next?5, 3, 42, 86, 15, 24, 25, 168, 2, 4, ?

  • Context: High School 
  • Thread starter Thread starter Moo Of Doom
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Discussion Overview

The discussion revolves around identifying the next number in a given sequence: 5, 3, 42, 86, 15, 24, 25, 168, 2, 4, ?. Participants explore various interpretations and potential patterns within the sequence, including the concept of palindromes.

Discussion Character

  • Exploratory, Debate/contested, Conceptual clarification

Main Points Raised

  • Some participants propose that the next number could be 6, while others argue it must be larger.
  • One participant suggests the answer is 35, receiving positive feedback from another.
  • There is a request for an explanation of the sequence, leading to the introduction of the concept of palindromes.
  • Several participants note that there are infinite possibilities for creating a palindrome from the sequence, providing examples of different palindromic sequences.
  • Another participant explains that if the number 4 is considered the middle of the sequence, the numbers before and after it mirror each other.
  • One participant reflects on the placement of commas in relation to the palindrome concept.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the next number in the sequence. Multiple competing views and interpretations of the sequence exist, particularly regarding the palindrome concept.

Contextual Notes

Limitations include the ambiguity of the sequence's rules and the dependence on the interpretation of palindromes, which leads to various potential answers.

Moo Of Doom
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What comes next?

5, 3, 42, 86, 15, 24, 25, 168, 2, 4, ?
 
Mathematics news on Phys.org
6 could it be
 
Nope, not 6.

Larger.
 
Answer: 35[/color]
- - - - - - - -
 
Good job, Bicycle Tree! You're good.
 
Is anybody going to explain?
 
Ok. The sequence is a palindrome.[/color]
 
In that case, 3 would serve as well (until moo added the extra condition).
 
what palindrome suppose to mean ?
 
  • #10
Man... darn... I saw it right after I looked at BicycleTree's response... Oh well.

ArielGenesis said:
what palindrome suppose to mean ?

Palindrome is the same backwards as it is forwards... they just have the commas in strange places.
 
  • #11
But there's an infinite number of options that makes it a palindrome. For example:
42861524251682435
142861524251682435
1142861524251682435
11142861524251682435
111142861524251682435
1111142861524251682435

And so on.
 
  • #12
If you take the 4 (from the 24) as the middle of the sequence, then the numbers before and after are the same. So directly before/after the 4 there is a 2 then a 5 then a 1 then a 6 and then an 8 and so on. I would have thought that the answer could have also been:
'3, 5' (but then there would be more commas on the right of the 4) [/color]

PS
 
Last edited:
  • #13
so the trick is just right at the comma. i got it. thanks all
 

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