LINCOLN, Neb. (AP) — A 57-year-old Lincoln man has gone to court to keep from being sent back to prison because state officials had miscalculated his sentence.

Bruce Caton filed his action on Tuesday, asking a judge to reduce his sentence to 10 years.

He was released in October, having served 10 years of his sentence of 10 to 20 years. But he wasn’t put on parole, because officials thought he’d served his full sentence. Now officials say he should have served five more years before discharge.

Caton is among dozens of prisoners mistakenly released early. Prison officials didn’t correctly calculate sentences for at least 101 inmates.

State officials are discussing legal steps needed to retrieve the inmates.