From ff260192480fda25385374aedf44a2d672002acd Mon Sep 17 00:00:00 2001
From: Jörg Sommrey <28217714+jo-37@users.noreply.github.com>
Date: Sun, 12 Mar 2023 22:26:36 +0100
Subject: Challenge 008 task 1

---
 challenge-008/jo-37/perl/ch-1.pl | 62 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100755 challenge-008/jo-37/perl/ch-1.pl

diff --git a/challenge-008/jo-37/perl/ch-1.pl b/challenge-008/jo-37/perl/ch-1.pl
new file mode 100755
index 0000000000..fad350e5b5
--- /dev/null
+++ b/challenge-008/jo-37/perl/ch-1.pl
@@ -0,0 +1,62 @@
+#!/usr/bin/perl -s
+
+use v5.16;
+use Test2::V0;
+use bigint;
+use List::Gen;
+use Math::Prime::Util 'divisor_sum';
+
+our ($tests, $examples, $verbose);
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV;
+usage: $0 [-examples] [-tests] [N]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+N
+    print the first N perfect numbers
+
+EOS
+
+
+### Input and Output
+
+gen_perfect()->take(shift)->say;
+
+
+### Implementation
+
+# No need to consider odd perfect numbers as none is known yet.  Thus
+# restricting to those generated from Mersenne primes.
+# Build a generator for even perfect primes.
+sub gen_perfect {
+	<2..>->map(sub {2**($_ - 1) * (2**$_ - 1)})
+        ->filter(sub {divisor_sum($_) == 2 * $_});
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        is gen_perfect()->take(5), [6, 28, 496, 8128, 33550336],
+            'task 1 from OEIS';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+
+        is gen_perfect()->get(5), 8589869056, 'next from OEIS';
+	}
+
+    done_testing;
+    exit;
+}
-- 
cgit