NAME
Math::NumSeq::CollatzSteps  steps in the "3n+1" problem
SYNOPSIS
use Math::NumSeq::CollatzSteps;
my $seq = Math::NumSeq::CollatzSteps>new;
my ($i, $value) = $seq>next;
DESCRIPTION
The number of steps it takes to reach 1 by the Collatz "3n+1" problem,
n > / 3n+1 if n odd
\ n/2 if n even
It's conjectured that any starting n will always eventually reduce to 1, so the number of steps is finite. There's no limit in the code on how many steps counted. Math::BigInt
is used if 3n+1 steps go past the usual scalar integer limit.
FUNCTIONS
See "FUNCTIONS" in Math::NumSeq for behaviour common to all sequence classes.
$seq = Math::NumSeq::CollatzSteps>new ()
$seq = Math::NumSeq::CollatzSteps>new (step_type => 'down')

Create and return a new sequence object.
The optional
step_type
parameter (a string) selects between"up" upward steps 3n+1 "down" downward steps n/2 "both" both up and down, which is the default
Random Access
$value = $seq>ith($i)

Return the number of steps to take
$i
down to 1. $bool = $seq>pred($value)

Return true if
$value
occurs as a step count. This is simply$value >= 0
.
SEE ALSO
Math::NumSeq, Math::NumSeq::JugglerSteps, Math::NumSeq::ReverseAddSteps
HOME PAGE
http://user42.tuxfamily.org/mathnumseq/index.html
LICENSE
Copyright 2011, 2012 Kevin Ryde
MathNumSeq 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.
MathNumSeq is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with MathNumSeq. If not, see <http://www.gnu.org/licenses/>.