Editing Sheffer sequence (section)

{{Use American English|date = March 2019}}
{{Short description|Type of polynomial sequence}}
In [[mathematics]], a '''Sheffer sequence''' or '''poweroid''' is a [[polynomial sequence]], i.e., a [[sequence]] {{math|(''p''<sub>''n''</sub>(''x'') : ''n'' {{=}} 0, 1, 2, 3, ...)}} of [[polynomial]]s in which the index of each polynomial equals its [[degree of a polynomial|degree]], satisfying conditions related to the [[umbral calculus]] in [[combinatorics]]. They are named for [[Isador M. Sheffer]].