Problem 69. Find the peak 3n+1 sequence value

Created by Cody Team

Difficulty:Rate

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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.

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Last Solution submitted on May 09, 2025

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Meg Noah on 14 Oct 2022

Broken link in description.

Dyuman Joshi on 14 Oct 2022

Link has been updated.

xb on 21 Aug 2023

why does it not work it can run successfully in matalb
function pmax = peakOfPeaks(nmax)
B=[]
for n=1:1:nmax
A=[];
if n==1
A=1
else A=n
end
while n~=1
if mod(n,2)==1
A=[A,3*n+1];
n=3*n+1
else A=[A,n/2];
n=n/2
end
end
B=[B,max(A)]
end
pmax=max(B)
end

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Problem 69. Find the peak 3n+1 sequence value

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Problem 69. Find the peak 3n+1 sequence value

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