Kondru Prasen, K. Raja Rama Gandhi, A Note on Universal Black Holes of a Dynamic System, BSMaSS Volume 9, The Bulletin of Society for Mathematical Services and Standards (Volume 9)
    We know that while considering a mathematical dynamical system by assigning a rule of cubing the individual digits of a particular number continuously, we will end up at some number which is recurring and can be called as the Universal Black hole of that particular system. However, some numbers only end at 153. The reasons for this occurrence will be discussed by a theorem. Also, we list such numbers which are < 5000.