Improved power-series method for confined one-dimensional   quantum-mechanical problems
  We propose two improvements to the well-known power series method for confined one-dimensional quantum-mechanical problems. They consist of the addition of a variational step were the energy plays the role of a variational parameter. We compare the rate of convergence of the three methods on an exactly-solvable model. We also outline possible generalizations of the approaches to more complex problems. 
Francisco M. Fern\'andez
quant-ph