A Collatz sequence is the sequence where, for a given number n, the next number in the sequence is either n/2 if the number is even or 3n+1 if the number is odd. See Problem 21 for more information.
Let c(n) be the sequence for n, and p(n) be the peak value of that sequence. For a given threshold nmax, find the highest peak value max(p(n)) for all Collatz sequences starting with integers between 1 and nmax.
Solution Stats
Problem Comments
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2 Comments
Hariprasad Baburajan
on 25 Dec 2018
Nice one
Zoltán Nagy
on 26 Apr 2019
Good problem!
Solution Comments
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1 Comment
A C
on 3 Jan 2019
How would I speed this up?
If I input nmax = 2^60, my program cannot finish.
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1 Comment
yurenchu
on 25 Dec 2016
This solution will fail for nmax = 2; so I had to swap the order of two lines. See Solution 1088355.
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1 Comment
Wycliff Dembe
on 20 Sep 2018
i'm totally lost with this!
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1 Comment
Ted
on 4 Oct 2013
wrong, corrected in soln 329062
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1 Comment
Evan
on 25 Jun 2013
I only feel justified in doing this because the previous best answer was a look-up table. :P
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1 Comment
Peter Wittenberg
on 28 Mar 2012
Clever pattern, but still gaming the system. This is not the absolute highest Collatz peak as you go to infinity. Yuval, you should be ashamed of submitting this without apologies.
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4 Comments
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1 older comment
Jed F.
on 30 Jan 2012
This really doesn't solve the problem it's just gaming the results.
Kevin Holst
on 14 Feb 2012
Boo.
Jean-Yves Tinevez
on 17 Feb 2012
Ooooooh this is evil.
Peter Wittenberg
on 28 Mar 2012
Pathetic
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