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- #!/usr/bin/perl
- use 5.014;
- use ntheory qw(:all);
- my $n = 12;
- # a(11) > 10^9
- # a(11) = 2690757467
- # a(12) = 36906080234
- my $from = 24300000000+1e8+1e9+1e9 + 1e9+1e9+1e9+1e9+1e9+1e9+1e9+1e9+1e9+1e9;
- # a(13) <= 848839845911, a(14) <= 1697679691826, a(15) <= 28860554761331, a(16) <= 57721109522666, a(17) <= 634932204749447. - ~~~~
- say "From: $from";
- forsemiprimes {
- if (not is_square($_)) {
- my ($x, $y) = factor($_);
- my $d = $y - $x;
- my $count = 0;
- for (; $count < $n and is_semiprime($d) and not is_square($d) ; ++$count) {
- ($x, $y) = factor($d);
- $d = $y - $x;
- }
- if ($count >= $n) {
- say "a($n) = $_ (ended at $d)";
- exit;
- ++$n;
- }
- }
- } $from, $from+1e9;
- # 21408927,158279834;
- # Check 20690757467-1e8, 24300000000-1e8-1e8
- __END__
- a(0) = 6 (ended at 1)
- a(1) = 34 (ended at 2)
- a(2) = 82 (ended at 3)
- a(3) = 226 (ended at 2)
- a(4) = 687 (ended at 2)
- a(5) = 4786 (ended at 2)
- a(6) = 14367 (ended at 2)
- a(7) = 28738 (ended at 2)
- a(8) = 373763 (ended at 2)
- a(9) = 21408927 (ended at 11)
- a(10) = 158279834 (ended at 5)
- a(11) = 2690757467 (ended at 5)
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