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- #!/usr/bin/perl
- # a(n) is the minimum number of distinct numbers with exactly n prime factors (counted with multiplicity) whose sum of reciprocals exceeds 1.
- # https://oeis.org/A374231
- # Known terms:
- # 3, 13, 96, 1772, 108336, 35181993
- use 5.036;
- use ntheory qw(:all);
- my $n = 7;
- my $sum = 0;
- my $index = 1;
- foralmostprimes {
- $sum += 1/$_;
- if ($index % 1e7 == 0) {
- say "[$index | $_] sum = $sum";
- }
- if ($sum > 1) {
- die "Found: $index (sum = $sum)";
- }
- ++$index;
- } $n, 1, ~0;
- __END__
- sum = 0.846524877737090592677330489673074
- sum = 0.846584110949018502846100517596571
- sum = 0.846643287378808079866941405886191
- sum = 0.846702407133082953728639844137568
- sum = 0.846761470325090899821824159996903
- ^C
- perl prog.pl 5301.53s user 111.64s system 97% cpu 1:32:10.01 total
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