The Weekly Challenge - 155

Monday, Mar 7, 2022| Tags: Perl, Raku










09. TASK #1: Fortunate Numbers

10. TASK #2: Pisano Period


Welcome to the Week #155. It is hard to believe the number. At times I feel like taking short break from the routine that I have been following for the last 3 years (almost). But then when I read the positive comments week after week by the dedicated members, I drop the idea completely. Here are some for you.

1. Ulrich Rieke

thank you for the fine tasks this week! Apparently, the prime number theme offers quite a number of variations. For me, trying to solve the tasks was a little distraction from the endless and permanent stream of sad news from the east of our common continent.

2. Duncan C. White

first nice and easy, second finds the first 8 Padovan Primes quickly, doesn’t find 9th or 10th PP in reasonable time and space.

3. Flavio Poletti

Hi! Please find my contribution for this week’s challenge. Thanks for all the energy!

4. Marton Polgar

thank you for the challenges as usual; very interesting second task indeed, as gfldex pointed out. :)

It is not that everything is rosy but lets change the topic.

First Monday of the month and time to declare another champion. It gives me immense pleasure to announce, Robert DiCicco, as our next champion. He is relative new to the team but in a short time he has become very prominent contributor. As of today, he has contributed 29 Perl and 6 Raku solutions. He is currently ranked #37 in the Guest Leaders board. He has so far contributed 6 Ruby and 4 Tcl solutions.

Let us welcome another member to the team, Jeff Armstrong. He shared his Raku solutions in the first week. Thank You.

Talking about contributions, I missed the opportunity to contribute once again. I always encourage others to contribute to Task #1 at least if they are running short of time since it usually doesn’t take much time. Here I am, not following my own advice. I am going through many ups and downs in my head right now. I will get back to the track soon, promise.

Blogs with Creative Title

1. Padovan Prime Directive: Find the Missing Permutations by Adam Russell.

2. Padovan is Missing with Raku and Perl by Arne Sommer.

3. TWC Episode 154 - Padawan Missing by Bruce Gray.

4. Who Took My Cheese? by Colin Crain.

5. Padovans Dog by Colin Crain.

6. A Quick One While I Do Other Things: Weekly Challenge #154 by Dave Jacoby.

7. The Weekly Challenge #154 - do and redo there is no try! by James Smith.

8. Perl Weekly Challenge 154: lazyness and recursion by Luca Ferrari.

9. Perming Perl plus Padovan primes by Peter Campbell Smith.

10. The Weekly Challenge 154: Missing Padovan by Roger Bell_West.

GitHub Repository Stats

1. Commits: 23,700 (+164)

2. Pull Requests: 5,741 (+33)

3. Contributors: 188 (+1)

4. Fork: 244 (+1)

5. Stars: 123 (+2)

Our solo sponsor Pete Sergeant has been a great support to keep us motivated. We are lucky that he agreed to continue the journey with us in the year 2021. I would like to personally thank Pete and his entire team for their generosity. It would be great if we could add few more to sponsor the prize money so that we could go back and declare weekly champions as we have done in the past. I hope and wish this will become possible in 2021. The amount doesn’t have to be huge. However, it would be nice to show off bunch of supporters. If an organisation comes forward and supports us then that would be the ultimate achievement.


Quick recap of The Weekly Challenge - 154 by Mohammad S Anwar.


Please check out Perl solutions review of The Weekly Challenge - 150 by Colin Crain.

If you missed any past reviews then please check out the collection.


If you missed any past reviews then please check out the collection.


Please take a look at the charts showing interesting data.

I would like to THANK every member of the team for their valuable suggestions. Please do share your experience with us.


Jeff Armstrong, an expert in Raku and Perl joined the Team PWC.

Please find out How to contribute?, if you have any doubts.

Please try the excellent tool EZPWC created by respected member Saif Ahmed of Team PWC.


Please checkout the guest contributions for the Week #154.

Please find past solutions by respected guests. Please share your creative solutions in other languages.

TASK #1 › Fortunate Numbers

Submitted by: Mohammad S Anwar

Write a script to produce first 8 Fortunate Numbers (unique and sorted).

According to Wikipedia

A Fortunate number, named after Reo Fortune, is the smallest integer m > 1 such that, for a given positive integer n, pn# + m is a prime number, where the primorial pn# is the product of the first n prime numbers.

Expected Output

3, 5, 7, 13, 17, 19, 23, 37

TASK #2 › Pisano Period

Submitted by: Mohammad S Anwar

Write a script to find the period of the 3rd Pisano Period.

In number theory, the nth Pisano period, written as π(n), is the period with which the sequence of Fibonacci numbers taken modulo n repeats.

The Fibonacci numbers are the numbers in the integer sequence:

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, ...

For any integer n, the sequence of Fibonacci numbers F(i) taken modulo n is periodic. The Pisano period, denoted π(n), is the value of the period of this sequence. For example, the sequence of Fibonacci numbers modulo 3 begins:

0, 1, 1, 2, 0, 2, 2, 1,
0, 1, 1, 2, 0, 2, 2, 1,
0, 1, 1, 2, 0, 2, 2, 1, ...

This sequence has period 8, so π(3) = 8.

Last date to submit the solution 23:59 (UK Time) Sunday 13th March 2022.


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