# Write a program for Hailstone Sequence in Python

Upasana | May 04, 2019 | 1 min read | 196 views |

## Hailstone Sequence

A hailstone sequence is a calculation of numbers that increase and decrease but eventually settles into a repeating pattern of the numbers 4, 2, 1. The sequence is generated by starting with any positive whole number greater than zero and completing the following steps:

• If the number is even, divide it by 2 to calculate a new number

• If the number is odd, multiple it by 3 and add 1 to calculate a new number

• Repeat the above process for calculated numbers until the sequence 4, 2, 1 is generated.

``````def generate_hale_seq(num):
lnum = [num]
while num != 1:
if (num%2) == 0:
num = num//2
lnum.append(num)
else:
num = (num * 3) + 1
lnum.append(num)
return lnum

print(generate_hale_seq(10))``````
Output
`[10, 5, 16, 8, 4, 2, 1]`

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