Math::NumSeq::DivisorCount -- how many divisors
use Math::NumSeq::DivisorCount; my $seq = Math::NumSeq::DivisorCount->new; my ($i, $value) = $seq->next;
The number of divisors of i,
1, 2, 2, 3, 2, 4, 2, 4, 3, 4, 2, 6, 2, 4, 4, 5, 2, 6, 2, ... starting i=1
i=1 is divisible only by 1 so value=1. Then i=2 is divisible by 1 and 2 so value=2. Or for example i=6 is divisible by 4 numbers 1,2,3,6 so value=4.
See "FUNCTIONS" in Math::NumSeq for behaviour common to all sequence classes.
$seq = Math::NumSeq::DivisorCount->new ()
Create and return a new sequence object.
$value = $seq->ith($i)
Return the number of prime factors in $i
.
This calculation requires factorizing $i
and in the current code after small factors a hard limit of 2**32 is enforced in the interests of not going into a near-infinite loop.
$bool = $seq->pred($value)
Return true if $value
occurs as a divisor count, which simply means $value >= 1
.
Math::NumSeq, Math::NumSeq::PrimeFactorCount
http://user42.tuxfamily.org/math-numseq/index.html
Copyright 2011, 2012, 2013, 2014 Kevin Ryde
Math-NumSeq is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.
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