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- #!/usr/bin/perl
- # a(n) begins the first run of least n consecutive numbers whose sum of divisors has the same set of distinct prime divisors.
- # https://oeis.org/A303693
- # Known terms:
- # 1, 5, 33, 3777, 20154, 13141793, 11022353993
- use 5.014;
- use ntheory qw(divisor_sum factor_exp);
- my $k = 6;
- # a(7) > 1e9
- #foreach my $n(2..10000) {
- for (my $n = 1e10; $n <= 1e11; ) {
- my $d = join ' ', map{$_->[0]} factor_exp(divisor_sum($n));
- my $c = 0;
- my $t = $n+1;
- while (join(' ', map{$_->[0]} factor_exp(divisor_sum($t))) eq $d) {
- ++$c;
- ++$t;
- if ($c == $k) {
- ++$k;
- say $n;
- }
- }
- $n = $t;
- }
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