From d2d37f4a76f7866fec9eae447068dfe519faedb3 Mon Sep 17 00:00:00 2001
From: Steven Wilson <steven1170@zoho.eu>
Date: Fri, 14 Jan 2022 11:25:06 +0000
Subject: add solution week 147 task 2 in perl

---
 challenge-147/steven-wilson/perl/ch-02.pl | 40 +++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 challenge-147/steven-wilson/perl/ch-02.pl

diff --git a/challenge-147/steven-wilson/perl/ch-02.pl b/challenge-147/steven-wilson/perl/ch-02.pl
new file mode 100644
index 0000000000..65f41f0585
--- /dev/null
+++ b/challenge-147/steven-wilson/perl/ch-02.pl
@@ -0,0 +1,40 @@
+#!/usr/bin/env perl
+# Week 147 Task 2
+# Pentagon Numbers
+# Write a sript to find the first pair of Pentagon Numbers
+# whose sum and difference are also a Pentagon Number.
+# Answer: First pair is 210 and 330
+
+use strict;
+use warnings;
+use feature qw/ say /;
+
+my @pentagonal_numbers = qw/ 1 /;
+my $first_pair_found   = 0;
+my $number             = 2;
+
+while ( not $first_pair_found ) {
+    my $next_pn = pentagonal_number($number);
+    for (@pentagonal_numbers) {
+        if (    is_pentagonal_number( $next_pn - $_ )
+            and is_pentagonal_number( $next_pn + $_ ) )
+        {
+            say "First pair is $_ and $next_pn";
+            $first_pair_found = 1;
+            last;
+        }
+    }
+    push @pentagonal_numbers, $next_pn;
+    $number++;
+}
+
+sub pentagonal_number {
+    my $n = shift;
+    return ( ( 3 * ( $n * $n ) ) - $n ) / 2;
+}
+
+sub is_pentagonal_number {
+    my $x         = shift;
+    my $remainder = ( sqrt( 24 * $x + 1 ) + 1 ) % 6;
+    $remainder > 0 ? return 0 : return 1;
+}
-- 
cgit 


From 8d0d58de8ba34070228f62b67b8c8fd7a4e27373 Mon Sep 17 00:00:00 2001
From: Steven Wilson <steven1170@zoho.eu>
Date: Fri, 14 Jan 2022 13:34:14 +0000
Subject: fix for floating point modulus

---
 challenge-147/steven-wilson/perl/ch-02.pl | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/challenge-147/steven-wilson/perl/ch-02.pl b/challenge-147/steven-wilson/perl/ch-02.pl
index 65f41f0585..d1bf716a76 100644
--- a/challenge-147/steven-wilson/perl/ch-02.pl
+++ b/challenge-147/steven-wilson/perl/ch-02.pl
@@ -3,11 +3,12 @@
 # Pentagon Numbers
 # Write a sript to find the first pair of Pentagon Numbers
 # whose sum and difference are also a Pentagon Number.
-# Answer: First pair is 210 and 330
+# Answer: First pair is 1560090 and 7042750
 
 use strict;
 use warnings;
 use feature qw/ say /;
+use POSIX qw/ fmod /;
 
 my @pentagonal_numbers = qw/ 1 /;
 my $first_pair_found   = 0;
@@ -35,6 +36,6 @@ sub pentagonal_number {
 
 sub is_pentagonal_number {
     my $x         = shift;
-    my $remainder = ( sqrt( 24 * $x + 1 ) + 1 ) % 6;
+    my $remainder = fmod( sqrt( 24 * $x + 1 ) + 1, 6 );
     $remainder > 0 ? return 0 : return 1;
 }
-- 
cgit 


From 91c79284313180190ba8873f00c1b643fa894a96 Mon Sep 17 00:00:00 2001
From: Steven Wilson <steven1170@zoho.eu>
Date: Fri, 14 Jan 2022 14:10:34 +0000
Subject: add solution week 147 task 2 in javascript

---
 challenge-147/steven-wilson/javascript/ch-02.js | 38 +++++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100755 challenge-147/steven-wilson/javascript/ch-02.js

diff --git a/challenge-147/steven-wilson/javascript/ch-02.js b/challenge-147/steven-wilson/javascript/ch-02.js
new file mode 100755
index 0000000000..36fadd5903
--- /dev/null
+++ b/challenge-147/steven-wilson/javascript/ch-02.js
@@ -0,0 +1,38 @@
+#!/usr/bin/env node
+// Week 147 Task 2
+// Pentagon Numbers
+// Write a sript to find the first pair of Pentagon Numbers
+// whose sum and difference are also a Pentagon Number.
+// Answer: First pair is 1560090 and 7042750
+
+var pentagonal_numbers = [1]
+var pair_found = false
+var number = 2
+
+while (!pair_found) {
+	let next_pn = pentagonal_number(number)
+	for (let i = 0; i < pentagonal_numbers.length; i++) {
+		if ((is_pentagonal_number(next_pn - pentagonal_numbers[i])) && 
+			(is_pentagonal_number(next_pn + pentagonal_numbers[i]))) {
+			console.log('First pair are ' + pentagonal_numbers[i] + ' and ' + next_pn)
+			pair_found = true
+			break
+		}
+	}
+	pentagonal_numbers.push(next_pn)
+	number++
+}
+
+function pentagonal_number (number) {
+	return ( ( 3 * ( number * number ) ) - number ) / 2
+}
+
+function is_pentagonal_number (number) {
+	let remainder = ( Math.sqrt( 24 * number + 1 ) + 1 ) % 6;
+    if ( remainder > 0 ) {
+    	return false
+    }
+    else {
+    	return true
+    }
+}
-- 
cgit