Get next sequential id

get_next_sequential

<?php

function get_next_sequential($nid) {
  $node = node_load($nid);
  foreach ($node->webform['components'] as $component) {
    if ($component['type'] == 'sequential_id') {
      $mid_component = $component;
    }
  }
  return webform_sequential_id_acquire_id($mid_component);
}

$next = get_next_sequential(4194858);
drush_print('Next sequential id: ' . $next);