Gary Williams, basketball coach at American University, has turned down an offer to become Seton Hall's coach and will be interviewed today in Boston for the vacancy at Boston College. All signs indicate that Williams, who also turned down the job at Duquesne last month, will take the Boston College job if it is offered.

Williams is one of seven coaches scheduled to be interviewed yesterday and today at Boston College, according to sources there. The list includes three coaches with more college experience and success than Williams, who led AU to back-to-back postseason tournaments and 20-victory seasons for the first time since the school went to Division I.

They are Jim Lynam, former American University and St. Joseph's coach now an assistant with the NBA's Portland Trail Blazers; Lou Campanelli, coach at James Madison University, and Don Casey, coach at Temple University.

The other coaches being interviewed are Bob Dukiet, coach at St. Peter's; Kevin Mackey, top assistant at Boston College who was recommended by Tom Davis after Davis quit as coach to accept the Stanford job last week, and Jim O'Brien, assistant coach at the University of Connecticut.

The details surrounding Williams' rejection of the Seton Hall job seem to indicate that he has decided to take the Boston College job if Bill Flynn, the athletic director at the Big East Conference school, offers it.

"He's not taking our job," said Richie Regan, Seton Hall's athletic director, asked yesterday about Williams' status at his school.

Sources said Regan wanted an answer Friday, but that Williams wanted to check out the Boston College opening before committing himself to rebuilding the last-place team in the Big East Conference. Williams, who has been at American four seasons, was an assistant to Davis at both Boston College and Lafayette. With fringe benefits, Davis made $70,000 to $80,000 at BC.

Regan said Seton Hall expected to name its coach very soon. Earlier, it had been reported that Williams was one of three finalists for the job. The others are Hoddy Mahon, who became interim coach when Bill Raftery resigned just prior to the season, and Dick Kuchen, a New Jersey native who is coach at the University of California. Regan refused comment when asked for names.

Williams, who was in Myrtle Beach, S.C., for a speaking engagement yesterday, confirmed that he was being interviewed today at Boston College.