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#!/usr/bin/perl
#
# Task #2: "Gapful Numbers
#
# Write a script to print first 20 Gapful Numbers greater than or equal
# to 100. See https://oeis.org/A108343 for details.
# In summary, Gapful Numbers are those numbers >= 100 that are divisible
# by the number formed by their first and last digit. Numbers up to 100
# trivially have this property and are excluded. eg. 100 is, because 100%10==0
# "
#
# My notes: cute. Sounds easy.
#
use feature 'say';
use strict;
use warnings;
use Function::Parameters;
#
# gapful( $i );
# Return 1 iff $i is a gapful number >= 100.
#
fun gapful( $i )
{
$i =~ /^(\d).*(\d)$/; # find first and largest digits
my $div = 10*$1 + $2;
return $i % $div == 0 ? 1 : 0;
}
die "Usage: ch-2.pl [FirstN]\n" if @ARGV>1;
my $n = shift // 20;
my $found = 0;
for( my $i = 100; $found<$n; $i++ )
{
next unless gapful( $i );
say $i;
$found++;
}
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