use v6;
sub endsWithOne($n --> Bool) {
my $digit;
my $sum = 0;
my $nn = $n;
loop {
while ($nn > 0) {
$digit = $nn % 10;
$sum += $digit²;
$nn = $nn div 10;
}
($sum == 1) and return True;
($sum == 89) and return False;
$nn = $sum;
$sum = 0;
}
}
my @ks = (7, 8, 11, 14, 17);
for @ks -> $k {
my @sums is default(0) = 1,0;
my $s;
for (1 .. $k) -> $n {
for ($n*81 ... 1) -> $i {
for (1 .. 9) -> $j {
$s = $j²;
if ($s > $i) { last };
@sums[$i] += @sums[$i-$s];
}
}
}
my $count1 = 0;
for (1 .. $k*81) -> $i { if (endsWithOne($i)) {$count1 += @sums[$i]} }
my $limit = 10**$k - 1;
say "For k = $k in the range 1 to $limit";
say "$count1 numbers produce 1 and ",$limit-$count1," numbers produce 89";
}
Output:
For k = 7 in the range 1 to 9999999
1418853 numbers produce 1 and 8581146 numbers produce 89
For k = 8 in the range 1 to 99999999
14255666 numbers produce 1 and 85744333 numbers produce 89
For k = 11 in the range 1 to 99999999999
15091199356 numbers produce 1 and 84908800643 numbers produce 89
For k = 14 in the range 1 to 99999999999999
13770853279684 numbers produce 1 and 86229146720315 numbers produce 89
For k = 17 in the range 1 to 99999999999999999
12024696404768024 numbers produce 1 and 87975303595231975 numbers produce 89