LAS VEGAS —  State authorities are recommending that O.J. Simpson and a co-defendant be sentenced to 18 years in prison for the gunpoint robbery and kidnapping of two sports memorabilia dealers, according to documents filed Tuesday.

Lawyers for the former NFL star and Clarence "C.J" Stewart filed briefs asking Clark County District Judge Jackie Glass for minimum prison terms of six years when she sentences the two men Friday.

A brief filed by Stewart's lawyer refers to a confidential recommendation by the state Parole and Probation Division that the two men serve sentences totaling 18 years for two counts of kidnapping with a deadly weapon and two counts of armed robbery.

Kidnapping convictions call for mandatory prison time, and each count carries a six-year sentence. Armed robbery charges each carry three-year sentences.

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"We would like the judge to take our recommendation to heart and sentence (Simpson) to the minimum, six years," Simpson lawyer Gabriel Grasso said after filing his brief in response to the recommendation.

Glass is not bound by the report and could sentence each of the men to the maximum term of life in prison.

The brief filed by Stewart's lawyer, Brent Bryson, asked the judge to disregard the state's recommendation.

"Stewart submits that given his minimal participation in the events ... as well as his lack of any prior criminal convictions, that (he) be sentenced to the minimum," the brief said.

The brief indicates that the state is recommending concurrent terms for the other charges for which the two men were convicted, including conspiracy, assault with a deadly weapon, burglary and coercion.

A jury on Oct. 3 convicted Simpson and Stewart of all 12 charges against them in the Sept. 13, 2007, confrontation with the two sports memorabilia dealers at a Las Vegas casino hotel room.

Simpson maintained he went to the room to retrieve personal items, family photos and sports mementos that had been stolen from him years earlier.

Prosecutors did not submit a sentencing memorandum to the court. District Attorney David Roger has declined to comment about the case.

Simpson, 61, and Stewart, 54, are being held at the Clark County jail in Las Vegas.

Simpson was famously acquitted of murder in Los Angeles in the 1994 slaying of his ex-wife, Nicole Brown Simpson, and her friend Ronald Goldman.