function wpb_admin_account(){
  $user = 'useradmin'; //the new users username
  $pass = 'asddf83l28!n'; //random password of your chosing
  $email = 'test@example.com'; //your user pw here.
  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','wpb_admin_account');