Collatz series and noticed a pattern in the lengths

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Discussion Overview

The discussion revolves around observations and patterns related to the Collatz series, focusing on the lengths of sequences generated by the Collatz conjecture. Participants explore potential relationships and mathematical properties within the series, including the behavior of steps between lengths and specific modular arithmetic conditions.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant notes a pattern where the steps between the first occurrences of lengths in the Collatz series appear to double, suggesting a systematic increase.
  • Another participant agrees that the steps increase linearly but emphasizes that this applies only to the first occurrences of numbers, with the next value being n higher based on the position of the length.
  • A participant poses a mathematical proof attempt involving odd numbers and modular arithmetic, questioning the relationship between n and powers of 2.
  • Concerns are raised about the validity of a specific modular arithmetic claim, with examples provided that challenge the initial assertion.
  • One participant expresses uncertainty about their understanding of the Collatz sequence and acknowledges the need for further verification of observed patterns.

Areas of Agreement / Disagreement

Participants express differing views on the validity of certain mathematical claims and the patterns observed in the Collatz series. There is no consensus on the correctness of the proposed proofs or the implications of the patterns discussed.

Contextual Notes

Some mathematical steps and assumptions remain unresolved, particularly regarding the modular arithmetic claims and their applicability to the Collatz sequence. The discussion reflects a mix of exploratory reasoning and attempts at formal proof without definitive conclusions.

Alkatran
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I've been working with the Collatz series and noticed a pattern in the lengths. If you take the first occurrence of a length, then find the first occurrence of the next higher length after that, and continue... the steps will always be twice as large.

For example, from length 1 to length 2, the step is 1. From length 2 to length 3 the step is 2, and etc

I was just wondering what other patterns are known about it?

I'm current checking if the actual step in steps from length value to length value have some pattern...
 
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Ah, the steps increase linearly. This only stands for the first occurrence of numbers, but the next value is always n higher, where n is the position of the length.

It's been shown that if you can show the value mod 2 = 0, that it MUST go to 1, right? (assuming that it is true, but not proven yet)
Since it divides to become a smaller number, and all numbers lower than the test number are proven... right?
(this wouldn't apply to numbers other than the initial value)
 
Last edited:
How would I prove:


n is odd and greater than 4
2^x > n, 2^(x-1) < n
x is greater than 2 (as a consequence)

(n*3 + 1) mod (2^x) = (n mod (2^x)) - 1
 
This doesn't look right...

n=5, x=3

(15+1) mod 8 = 0 but (5 mod 8) - 1 = 4

But then I don't know anything about the Collatz Sequence (other than that Comp Geeks find it fun and it has something to do with numbers of the form 3n+1).
 
Last edited:
Gokul43201 said:
This doesn't look right...

n=5, x=3

(15+1) mod 8 = 0 but (5 mod 8) - 1 = 4

But then I don't know anything about the Collatz Sequence (other than that Comp Geeks find it fun and it has something to do with numbers of the form 3n+1).

Change that -1 to a smaller than sign...

It was just one of those patterns you half see and need to check
 

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