Merge pull request #6234 from PerlBoy1967/branch-for-challenge-168

w168 - Task 1 & 2

2 files changed, 98 insertions, 0 deletions

diff --git a/challenge-168/perlboy1967/perl/ch-1.pl b/challenge-168/perlboy1967/perl/ch-1.pl
new file mode 100755
index 0000000000..50073d073d
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+++ b/challenge-168/perlboy1967/perl/ch-1.pl
@@ -0,0 +1,51 @@
+#!/bin/perl
+
+=pod
+
+The Weekly Challenge - 168
+ - https://theweeklychallenge.org/blog/perl-weekly-challenge-168/#TASK1
+
+Author: Niels 'PerlBoy' van Dijke
+
+Task 1: Perrin Prime
+Submitted by: Roger Bell_West
+
+The Perrin sequence is defined to start with [3, 0, 2]; after that, term N is the sum of 
+terms N-2 and N-3. (So it continues 3, 2, 5, 5, 7, ….)
+
+  || A Perrin prime is a number in the Perrin sequence which is also a prime number.
+
+Calculate the first 13 Perrin Primes.
+
+f(13) = [2, 3, 5, 7, 17, 29, 277, 367, 853, 14197, 43721, 1442968193, 792606555396977]
+
+=cut
+
+use v5.16;
+use warnings;
+
+use Math::Prime::XS qw(is_prime);
+
+# Prototype(s)
+sub perrin ($);
+
+my %p;
+my ($n,$p) = (0,1);
+while ($n < 13) {
+  my $pN = perrin($p++);
+  if (is_prime($pN) && !exists $p{$pN}) {
+    say $pN; $p{$pN}++; $n++;
+  }
+}
+  
+sub perrin ($) {
+  my ($n) = @_;
+
+  state $p = [3, 0, 2];
+
+  return $p->[$n] if defined $p->[$n];
+
+  $p->[@$p] = $p->[@$p-2] + $p->[@$p-3] while (!defined $p->[$n]);
+
+  return $p->[$n];
+}
diff --git a/challenge-168/perlboy1967/perl/ch-2.pl b/challenge-168/perlboy1967/perl/ch-2.pl
new file mode 100755
index 0000000000..6f710f9110
--- /dev/null
+++ b/challenge-168/perlboy1967/perl/ch-2.pl
@@ -0,0 +1,47 @@
+#!/bin/perl
+
+=pod
+
+The Weekly Challenge - 168
+ - https://theweeklychallenge.org/blog/perl-weekly-challenge-168/#TASK2
+
+Author: Niels 'PerlBoy' van Dijke
+
+Task 2: Home Prime
+Submitted by: Mohammad S Anwar
+
+You are given an integer greater than 1.
+
+Write a script to find the home prime of the given number.
+
+In number theory, the home prime HP(n) of an integer n greater than 1 is the 
+prime number obtained by repeatedly factoring the increasing concatenation of 
+prime factors including repetitions.
+
+Further information can be found on Wikipedia and OEIS.
+
+=cut
+
+use v5.16;
+use warnings;
+
+use Math::Prime::XS qw(is_prime);
+use Math::Factor::XS qw(prime_factors);
+use Try::Tiny;
+
+# prototype(s)
+sub homePrime ($);
+
+for my $n (2 .. 1000) {
+  my  $h = homePrime($n);
+  printf "%d\t=> %s\n", $n, (!defined $h ? 'Too big to handle' : $h);
+}
+
+sub homePrime ($) {
+  my ($n) = @_;
+
+  try { $n  = join '', prime_factors($n) while (!is_prime($n)) }
+  catch { return };
+
+  return $n;
+}