Math::NumSeq::WoodallNumbers -- Woodall numbers i*2^i-1
use Math::NumSeq::WoodallNumbers; my $seq = Math::NumSeq::WoodallNumbers->new; my ($i, $value) = $seq->next;
The Woodall numbers i*2^i-1 starting from i=1,
1, 7, 23, 63, 159, 383, 895, 2047, 4607, 10239, ...
See "FUNCTIONS" in Math::NumSeq for behaviour common to all sequence classes.
$seq = Math::NumSeq::WoodallNumbers->new ()
Create and return a new sequence object.
Move the current sequence position to
$i. The next call to
next() will return
$i and corresponding value.
$value = $seq->ith($i)
$i * 2**$i - 1.
$bool = $seq->pred($value)
Return true if
$value is a Woodall number, ie. is equal to i*2^i-1 for some i.
$i = $seq->value_to_i_floor($value)
Return the index i of
$value or of the next Woodall number below
$i = $seq->value_to_i_estimate($value)
Return an estimate of the i corresponding to
An easy over-estimate is l=log2(value), which reverses value=2^l. It can be reduced by the bit length of that l as i=l-log2(l) to get closer.
Copyright 2011, 2012, 2013 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.
Math-NumSeq 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 Math-NumSeq. If not, see <http://www.gnu.org/licenses/>.