blob: bd4601721a6eb7b4bc94f5f92fd8c1aab7fe26ba (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
#!/usr/bin/env perl
use strict;
use warnings;
use feature qw{ say signatures };
no warnings qw{ experimental::signatures };
use List::Util qw{sum};
say join "\n", perfect_numbers();
sub perfect_numbers {
my @numbers;
my $p = 1;
while ( scalar @numbers < 5 ) {
$p++;
next unless is_prime($p);
my $q = $p - 1;
my $o = ( 2**$q ) * ( ( 2**$p ) - 1 );
next unless is_perfect($o);
push @numbers, $o;
}
return @numbers;
}
sub is_perfect ( $n ) {
my @factors = factor($n);
my $sum = sum @factors;
return $sum == $n ? 1 : 0;
}
sub is_prime ( $n ) {
my @factors = factor($n);
return scalar @factors == 1 ? 1 : 0;
}
sub factor ( $n ) {
my @factors;
for my $i ( 1 .. $n - 1 ) {
push @factors, $i if $n % $i == 0;
}
return @factors;
}
|
