The **collatz sequence** is a #key# conjecture: speculation #key# in mathematics that follows a sequence. This sequence is defined below:

* The sequence begins with any positive integer, say `n` 
* If the integer `n` is odd, the next number in sequence would be `3n+1`
* If  the integer `n` is even, the next number in sequence would be `n/2`
* The sequence will continue until digit `1` is encountered



# Example
Let's understand this with an example.

Assuming that `n` is `11`:

1. Since `11` is odd, the second number in the sequence is $3 * 11 + 1  = 34$, i.e., `3n=1`

**Now we have [11, 34,...]**

2. Since `34` is even, the next number is $34 / 2 = 17$, i.e., `n/2`

**Now we have [11, 34, 17...]**

3. `17` is odd, so I suppose you know what to do!

> Please note that the sequence continues until digit 1 is encountered. Here is how it goes: **11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1**
 

Now that we know what the Collatz sequence is let's try coding it.

# Algorithm
1. Read an integer, `n`
2. If `n` is even, `n=n/2`
3. If `n` is odd, `n=3n+1`
4. Repeat steps `2` and `3` until `n` becomes `1`




#include<stdio.h>
int main(){
  int n = 11;
  while(n > 1){
    if(n % 2 == 0){ //for even numbers
      n = n / 2;
      printf("%d\n", n);
    }
    else{ //for odd numbers
      n = n * 3 + 1;
      printf("%d\n", n);
    }
  }
  return 0;
}

def collatz_sequence(n):
    collatz_list=list() #list to store the values of sequence
    
    while (n!=1) :
        collatz_list.append(n) 
        #if n is even
        if (n%2==0) :
            n=n//2
        else:
          #if n is odd
            n=(3*n)+1
    collatz_list.append(1)  #print 1 in the end   
    l=len(collatz_list)

    print("The length of collatz sequence is", l)
    print("The sequence is :")
    for i in range(0,l):
      print(collatz_list[i])

#driver code  
collatz_sequence(11)

Python

How to implement the collatz sequence in C and Python

Generate the Collatz sequence by repeatedly applying specified operations to reach 1, based on the integer's parity.

How to implement the collatz sequence in C and Python

Example

Algorithm

Code