Sequence: nth number with exactly n divisors: Difference between revisions
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{{draft task}} |
{{draft task}} |
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Calculate the sequence where each term <strong>a<sub>n</sub></strong> is the <strong>n<sup>th</sup></strong> that has '''n''' divisors. |
Calculate the sequence where each term <strong>a<sub>n</sub></strong> is the <strong>n<sup>th</sup></strong> that has '''n''' divisors. |
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;Task |
;Task |
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Show here, on this page, at least the first 10 terms of the sequence. |
Show here, on this page, at least the first '''10''' terms of the sequence. |
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;See also |
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;Related tasks |
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:*[[Sequence: smallest number greater than previous term with exactly n divisors]] |
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:*[[Sequence: smallest number with exactly n divisors]] |
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=={{header|Perl 6}}== |
=={{header|Perl 6}}== |
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Revision as of 16:04, 11 April 2019
Sequence: nth number with exactly n divisors is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.
Calculate the sequence where each term an is the nth that has n divisors.
- Task
Show here, on this page, at least the first 10 terms of the sequence.
- See also
- Related tasks
Perl 6
<lang perl6>sub div-count (\x) {
return 2 if x.is-prime;
+flat (1 .. x.sqrt.floor).map: -> \d {
unless x % d { my \y = x div d; y == d ?? y !! (y, d) }
}
}
my $limit = 15;
my @primes = grep { .is-prime }, 1..*; @primes[$limit]; # prime the array. SCNR
put "\nFirst 15 terms of OEIS:A073916"; put (1..$limit).hyper(:2batch).map: -> $n {
($n > 4 and $n.is-prime) ??
exp($n - 1, @primes[$n - 1]) !!
do {
my $i = 0;
my $iterator = $n %% 2 ?? (1..*) !! (1..*).map: *²;
$iterator.first: {
next unless $n == .&div-count;
next unless ++$i == $n;
$_
}
}
};</lang>
First 15 terms of OEIS:A073916 1 3 25 14 14641 44 24137569 70 1089 405 819628286980801 160 22563490300366186081 2752 9801