LINCOLN, Neb. (AP) — A former Lincoln teacher convicted of sexually assaulting a student is appealing his sentence.

Online court records say an attorney for 23-year-old Jackson Hedrick on Tuesday filed a notice of appeal with the Nebraska Appeals Court. A hearing date has not been set. Hedrick is claiming that the sentence is excessive.

On Dec. 10 Hedrick was sentenced to 20 to 30 years in prison. He pleaded guilty to sexual assault. Hedrick lost his job in March following allegations of an inappropriate relationship with the 14-year-old student.

Hedrick graduated last year from the University of Nebraska-Lincoln with a bachelor’s degree in education and was hired to teach social studies at Irving Middle School in August 2014.