Seeking help removing first 2 (or 3) characters from string

PHP
1

In <div id=“chart_rt”>%3$s</div> below, it is populated with a string that always begins with a number followed by a colon (from 1: to 25:). I see that ltrim removes characters from the beginning of a string but I don’t see how to compensate for the extra character in 10: through [B]25:

[/B]

function wp_rss( $url, $num_items = -1 ) {
    if ( $rss = fetch_rss( $url ) ) {
        echo '<div id="charts">';

        if ( $num_items !== -1 ) {
            $rss->items = array_slice( $rss->items, 0, $num_items );
        }
//start count
$i = 1;
        foreach ( (array) $rss->items as $item ) {
            printf(
                '<div id="chart_lt">'.$i.'</div><div id="chart_rt">%3$s</div>',
                esc_url( $item['link'] ),
                esc_attr( strip_tags( $item['description'] ) ),
                htmlentities( $item['title'] )
            );
//increment
$i++;
        }

        echo '</div>';
    } else {
        _e( 'An error has occurred, which probably means the feed is down. Try again later.' );
    }
}