“…Numerical and perturbation approaches to solve eqn (1.2) have been considered in Horedt [20,21], Bender [5] and Lema [29]. Other methods have also been invoked for the solution of eqn (1.2) (see Roxbough and Stocken [36], Adomian et al [2], Shawagfeh [38], Burt [8], Wazwaz [41] and Liao [27]). It is known that for r = 0, 1 and 5, eqn (1.2) has exact solutions (Chandrasekhar [9], Davis [11], Datta [10] and Wrubel [43]).…”