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- #!/usr/bin/perl
- # Daniel "Trizen" Șuteu
- # Date: 21 August 2016
- # Edit: 07 April 2019
- # https://github.com/trizen
- # https://projecteuler.net/problem=357
- # Runtime: 9.549s
- use 5.014;
- use strict;
- use integer;
- use ntheory qw(:all);
- my $sum = 0;
- forprimes {
- my $n = $_-1;
- if (is_square_free($n) and vecall { is_prime($_ + $n/$_) } divisors($n)) {
- $sum += $n;
- }
- } 100_000_000;
- say $sum;
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