Wronskian differential formula for confluent supersymmetric quantum mechanics

► A Wronskian differential formula is obtained. ► This formula can be used to apply a confluent second-order SUSY transformations. ► It involves a parametric derivative with respect to the factorization energy. ► In many cases this expression is simpler to calculate than the previous one. ► This alternative method is applied to the free particle and to one Lame potential.