I need the following output in php

Question

12345
678910
1112131415
1617181920

Answer 1

okay?
$a=1;
for($i=0;$i<20;$i++)
{ echo $a++;
}

Answer 2

With the line breaks:

$a=1;
for($i = 0; $i < 4; $i++) {
for($e = 0; $e < 5; $e++) {
echo $a++;
}
echo "\n";
}