4 files changed, 7 insertions, 6 deletions
diff --git a/challenge-147/wlmb/perl/ch-1.pl b/challenge-147/wlmb/perl/ch-1.pl
index 1fa2fbebe8..b2842052a4 100755
--- a/challenge-147/wlmb/perl/ch-1.pl
+++ b/challenge-147/wlmb/perl/ch-1.pl
@@ -7,7 +7,7 @@ use v5.12;
 use warnings;
 use PDL;
 use PDL::NiceSlice;
-use POSIX qw(); # don't import to avoid name collisions with PDL
+use POSIX (); # don't import to avoid name collisions with PDL
 use Text::Wrap qw(wrap $columns $break);
 
 die "Usage: ./ch-1.pl size_of_sieve number_of_truncatable_primes [base]\n"
diff --git a/challenge-147/wlmb/perl/ch-2.pl b/challenge-147/wlmb/perl/ch-2.pl
index 88eecdda76..f2edfb1a85 100755
--- a/challenge-147/wlmb/perl/ch-2.pl
+++ b/challenge-147/wlmb/perl/ch-2.pl
@@ -5,12 +5,13 @@
 # See https://wlmb.github.io/2022/01/10/PWC147/#task-2-pentagon-numbers
 use v5.12;
 use warnings;
-use bigint;
+use POSIX qw(floor);
 use Time::HiRes qw(time);
 
 die "Usage: ./ch-2.pl largest_index\n" unless @ARGV==1;
 my $N=shift;
 my $start=time();
+use integer;
 J:
     foreach my $j(2..$N){
         my $p=$j*(3*$j-1)/2;
@@ -21,10 +22,12 @@ J:
                 last J if pentagonal($q+$p) && pentagonal($p-$q);
         }
 }
+no integer; # don't truncate time
 say "Time: ", time()-$start;
+use integer;
 sub pentagonal {
     my $p=24*shift()+1;
-    my $s=sqrt($p);
+    my $s=floor(sqrt($p));
     return $s**2==$p && $s%6==5;
 }
 sub index_of {
diff --git a/challenge-147/wlmb/perl/ch-2a.pl b/challenge-147/wlmb/perl/ch-2a.pl
index 038b9630d3..5dca4ebda9 100755
--- a/challenge-147/wlmb/perl/ch-2a.pl
+++ b/challenge-147/wlmb/perl/ch-2a.pl
@@ -14,8 +14,7 @@ my $N=shift;
 my $start=time();
 my $n=zeroes(long, $N)->xvals+1;
 my $p=$n*(3*$n-1)/2;
-my $check=pentagonal($p);
-for my $i (2..$p->nelem){
+for my $i (1..$p->nelem){
     my $pi=$p(($i-1));
     my $pass=which(pentagonal($pi+$p) & pentagonal($pi-$p));
     next unless $pass->nelem;
diff --git a/challenge-147/wlmb/perl/ch-2b.pl b/challenge-147/wlmb/perl/ch-2b.pl
index c029154bc9..320dfedddc 100755
--- a/challenge-147/wlmb/perl/ch-2b.pl
+++ b/challenge-147/wlmb/perl/ch-2b.pl
@@ -14,7 +14,6 @@ my $N=shift;
 my $start=time();
 my $n=zeroes(long, $N)->xvals+1;
 my $p=$n*(3*$n-1)/2;
-my $check=pentagonal($p);
 my $pass=whichND(pentagonal($p+$p(*1)) & pentagonal($p-$p(*1)));
 die "No solution found. Try to increase the largest_index" unless $pass->dim(1)>0;
 my $ij=$pass(:,(0))+1;