# Copyright 2010, 2011, 2012, 2013, 2014 Kevin Ryde
# This file is part of Math-NumSeq.
#
# 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/>.
package Math::NumSeq::Beastly;
use 5.004;
use strict;
use List::Util 'max';
use vars '$VERSION', '@ISA';
$VERSION = 71;
use Math::NumSeq;
@ISA = ('Math::NumSeq');
*_is_infinite = \&Math::NumSeq::_is_infinite;
# uncomment this to run the ### lines
#use Smart::Comments;
# use constant name => Math::NumSeq::__('Beastly Numbers');
use constant description => Math::NumSeq::__('Numbers which contain "666". The default is decimal, or select a radix.');
use constant i_start => 1;
use constant characteristic_increasing => 1;
use constant characteristic_integer => 1;
use constant parameter_info_array =>
[
{ name => 'radix',
share_key => 'radix_min_7',
type => 'integer',
display => Math::NumSeq::__('Radix'),
default => 10,
minimum => 7, # less than 7 there's no beastly values
width => 3,
description => Math::NumSeq::__('Radix, ie. base, for the values calculation. Default is decimal (base 10).'),
},
];
#------------------------------------------------------------------------------
# cf A131645 the beastly primes
sub oeis_anum {
my ($self) = @_;
return ($self->{'radix'} == 10
? 'A051003'
: undef);
}
# OEIS-Catalogue: A051003 radix=10
#------------------------------------------------------------------------------
sub values_min {
my ($self) = @_;
my $radix = $self->{'radix'};
return (6*$radix+6)*$radix+6; # at i=0
}
sub rewind {
my ($self) = @_;
my $radix = $self->{'radix'};
$self->{'i'} = $self->i_start;
$self->{'target'} = (6*$radix+6)*$radix+6;
$self->{'cube'} = $radix*$radix*$radix;
$self->{'value'} = $self->{'target'} - 1;
}
sub next {
my ($self) = @_;
if ($self->{'radix'} < 7) {
return;
}
my $value = $self->{'value'};
for (;;) {
if ($self->pred(++$value)) {
return ($self->{'i'}++, ($self->{'value'} = $value));
}
}
}
sub pred {
my ($self, $value) = @_;
{
my $int = int($value);
if ($value != $int) {
return 0;
}
$value = $int; # prefer BigInt if input BigFloat
}
my $radix = $self->{'radix'};
if ($radix < 7) {
return 0; # no digit 6s at all if radix<7
}
if ($radix == 10) {
return ($value =~ /666/);
}
if (_is_infinite($value)) {
return 0;
}
my $cube = $self->{'cube'}; # radix^3
my $target = $self->{'target'}; # 666 in radix
for (;;) {
if (($value % $cube) == $target) {
return 1;
}
if ($value < $cube) {
return 0;
}
$value = int($value/$radix);
}
}
1;
__END__
=for stopwords Ryde Math-NumSeq radix
=head1 NAME
Math::NumSeq::Beastly -- numbers containing digits "666"
=head1 SYNOPSIS
use Math::NumSeq::Beastly;
my $seq = Math::NumSeq::Beastly->new;
my ($i, $value) = $seq->next;
=head1 DESCRIPTION
This sequence is the beastly numbers which are those with "666" somewhere in
their digits. The default is decimal, or a radix can be given.
666, 1666, 2666, 3666, 4666, 5666,
6660, 6661, 6662, ..., 6669,
7666, 8666, 9666,
etc
=head1 FUNCTIONS
See L<Math::NumSeq/FUNCTIONS> for behaviour common to all sequence classes.
=over 4
=item C<$seq = Math::NumSeq::Beastly-E<gt>new ()>
=item C<$seq = Math::NumSeq::Beastly-E<gt>new (radix =E<gt> $r)>
Create and return a new sequence object.
An optional C<radix> parameter selects a base other than decimal. If
C<radix> is 6 or less then there's no "6" digits at all and the sequence has
no values.
=item C<$bool = $seq-E<gt>pred ($value)>
Return true if C<$value> has "666" in its digits, in the requested C<radix>.
=back
=head1 SEE ALSO
L<Math::NumSeq>,
L<Math::NumSeq::Repdigits>
=head1 HOME PAGE
L<http://user42.tuxfamily.org/math-numseq/index.html>
=head1 LICENSE
Copyright 2010, 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.
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/>.
=cut