Hugh Jackman was one of the lone bright spots at the Broadway box office last week, landing squarely in the millionaires club and helping to counter a slowdown at nearly every other show on the boards.Jackman’s concert outing “Hugh Jackman, Back on Broadway” ($1,210,974) played its first eight previews, kicking things off by breaking the house record at the Broadhurst Theater set last season by the Al Pacino-toplined revival of “The Merchant of Venice.” “Jackman” looks poised to remain a sales powerhouse throughout its 10-week run, with the performer having proven his blockbuster B.O. draw during previous visits to the Main Stem, “The Boy From Oz” and “A Steady Rain.” Only a few other Rialto productions managed to pick up steam last week, including seemingly invincible “The Book of Mormon” ($1,351,169) and “Relatively Speaking” ($741,903), the trio of one-acts that played its first full frame after opening. Otherwise sales generally slackened. Broadway box office often tapers off around this time of year in a phenomenon that’s often attributed to the clock-change that comes with the end of daylight saving time — but that doesn’t explain sales last week, with this year’s clock switchover skedded for Sunday. In any event, tourists seem less likely to visit New York (and Broadway) around now anyway, with year-end holiday vacations looming on the horizon. Plus, last week included the distractions of Halloween weekend to distract consumers’ attention away from the Main Stem. Among the shows hardest hit by the frame’s downturn were “Memphis” ($637,715), down by close to 20%, as well as “Mary Poppins” ($637,776) and “Priscilla Queen of Desert” ($719,758), both off by notable margins. It was Jackman’s show that helped keep Broadway cume up, with the infusion of coin from “Back on Broadway” bringing overall grosses to $21.2 million for 28 total shows. That’s down about $300,000 compared to the prior sesh. Also adding to last week’s pot was “Seminar” ($143,850), the Alan Rickman starrer that played its first three previews. Also in previews, “Other Desert Cities” ($426,707) continued to play to nearly packed houses, whereas tuner revival “Godspell” ($264,916) has proven slower to catch on.