++ed by:
Kevin Ryde
and 1 contributors

# NAME

Math::NumSeq::UndulatingNumbers -- numbers with alternating digits ABABAB...

# SYNOPSIS

`````` use Math::NumSeq::UndulatingNumbers;
my \$seq = Math::NumSeq::UndulatingNumbers->new (radix => 10);
my (\$i, \$value) = \$seq->next;``````

# DESCRIPTION

This is the sequence of numbers with digits ABABAB... alternating between two values,

``````    0 ... 99,
101, 111, 121, 131, ... 191,
202, 212, 222, 232, ... 292,
...
909, 919, 929, 939, ... 999,
1010, 1111, 1212, ... 1919,
...``````

Numbers with just 1 or 2 digits are A or AB and are considered of undulating form. This means all numbers up to 99 are undulating.

The default is decimal or the optional `radix=>\$r` can select another radix.

In binary the only two digits are 0 and 1 and the high digit must be 1, so it ens up being just 101... and 111...

``````    0, 1, 10, 11, 101, 111, 1010, 1111, 10101, 11111, ...
(in binary)``````

# FUNCTIONS

See "FUNCTIONS" in Math::NumSeq for behaviour common to all sequence classes.

`\$seq = Math::NumSeq::UndulatingNumbers->new ()`
`\$seq = Math::NumSeq::UndulatingNumbers->new (radix => \$r)`

Create and return a new sequence object. The default radix is 10.

`\$bool = \$seq->pred(\$value)`

Return true if `\$value` is an undulating number, ie. has digits of the form ABABAB...

`\$i = \$seq->value_to_i_floor(\$value)`
`\$i = \$seq->value_to_i_estimate(\$value)`

Return the i for the undulating number <= \$value.

Math::NumSeq

http://user42.tuxfamily.org/math-numseq/index.html

Copyright 2010, 2011, 2012 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/>.