public static function pj_enfn($es)
    {
        $en = array();
        $en[0] = static::C00 - $es * (static::C02 + $es * (static::C04 + $es * (static::C06 + $es * static::C08)));
        $en[1] = $es * (static::C22 - $es * (static::C04 + $es * (static::C06 + $es * static::C08)));
        $t = $es * $es;
        $en[2] = $t * (static::C44 - $es * (static::C46 + $es * static::C48));
        $t *= $es;
        $en[3] = $t * (static::C66 - $es * static::C68);
        $en[4] = $t * $es * static::C88;

        return $en;
    }