LOS ANGELES -- Brandon Tartikoff made his last appearance before the nation's TV press as NBC Entertainment president yesterday and neither will soon forget it ...

Two days after the network announced he had been elevated to chairman of the new NBC Entertainment Group, arguably the best (and certainly the funniest) TV programmer in the business kicked things off by joining Will Smith, star of the promising "Fresh Prince of Bel Air" series, in a rap number that promoted the network's nine new fall series and poked fun at his ascendancy to the new top job ...

The music had barely died away when some 100 or so of the writers put on Bart Simpson masks that had been smuggled past NBC staffers, a reminder to Tartikoff of the 8 p.m. Thursday night challenge to "The Cosby Show" that the FOX cartoon series will present next season ...

"That's ugly," said Smith ...

"This is what I dream about at night," said Tartikoff, who said the new gray hairs on his 41-year-old head were due to "The Simpsons" on one side and ABC's "America's Funniest Home Videos" on the other ...

In a Q & A session that then stretched nearly two hours, he and Warren Littlefield, his longtime deputy and successor as Entertainment president, proceeded to sketch just where the No. 1 primetime network hopes to go in the 1990-91 season and to offer a few more details of just how he had arrived at the decision to leave day-to-day operations at the network so he could devote more time to "the big picture" at NBC ...

Tartikoff announced that starting the night of Aug. 23, NBC Entertainment will "double pump" six of the nine new series, airing pilot episodes twice in different time slots before the regular season gets underway ...

Chosen for the unusual campaigns were the medical anthology "Lifestories," "Ferris Bueller," "Law & Order," "Parenthood," "Hull High" and "Working It Out" ...

He said exact schedules for the double pumping would be announced next week ...

Tartikoff also said that the pilot of a one-hour "information and variety show" hosted by Washington's very own Larry King will air at 8 p.m. Sunday, Oct. 28 ...

(The bad news is that the night of Oct. 28 could very well be during the World Series on CBS) ...

Littlefield said later that there would be elements of the old "Ed Sullivan Show" in the King pilot but that it would also include taped interviews and features conducted by the CNN and Mutual talk show host ...

Tartikoff also said that one of his favorite short-run spring series, "Shannon's Deal," is being renewed as a midseason replacement -- and proceeded to stage a mock contract-signing during which "Shannon" star Jamey Sheridan, in his role as a lawyer, questioned the contract and asked, "Can we get back to you on that?" (I guess you had to be there for that one) ...

Littlefield then announced two more series as midseason replacements, including "Blossom," about a 13-year-old and her dad (which didn't do too well in a network tryout this year), and "Sisters," a one-hour drama about the "unique relationships between four sisters" from Lorimar ...

Tartikoff said the nine new series share two important characteristics:

"Overall, they're clever" and any one of the nine will prove to be "someone's favorite show" among the many specific new audiences targeted by the network.

He emphasized that while audiences may be getting smaller for each show, the spectrum of choices is getting wider for viewers ...

"Audiences have grown up" after being exposed to TV for some 40 years, said Tartikoff ...

He said the NBC schedule reflects a willingness to "take more chances" in part because audiences have been signaling for "quite a while" that they're less conservative ...

Regarding his job change, Tartikoff told the critics he had talked to NBC president Bob Wright in January about the prospect that "sooner rather than later I'm not going to want to do this job" (after 12 years as the top programmer for the network) ...

He said the fact that contracts of both Littlefield and Perry Simon, who Tuesday succeeded the new Entertainment president as executive vice president for primetime programs, were both up in June made the decision for a restructuring considerably more urgent ...

Littlefield confirmed speculation that while he had been thinking of a move, he had wanted to stay at NBC and had never gotten to the point of entertaining outside offers this spring ...

Tartikoff said it is entirely possible that NBC parent General Electric could be in the market for a movie studio somewhere down the road should the Federal Communications Commission relax current rules that limit network participation in the production and syndication of programs -- and that he would be the person to run it ("a big toy to play with") ...

Regarding his new brief as chairman of the Entertainment Group, Tartikoff said yesterday he thinks the network-owned stations (Channel 4 in Washington, for instance) "ought to be more viable farm teams for us," suggesting they could produce late-night programming or possibly comedies and "reality" programming good enough for the NBC primetime schedule ...

Although there is some innuendo in the content of pilots for shows like "Hull High," a high school musical show headed for the 7 p.m. Sunday timeslot, the TV writers have been less critical of the content of the NBC lineup than they were of CBS's earlier this week ...

And yesterday Tartikoff, who was roundly criticized two years ago on the subject, observed, chairmanlike, that "you don't have to be over the boundaries of good taste to be contemporary" in the current network competition ...

Later, he suggested to reporters that CBS's flirtation with racy language in shows like "Uncle Buck" would seem to be the case of a third-place network's need "to throw some flares up in the air" to gain viewer attention ...

And Finally

What would a TV Column be without a couple of ratingzz to test the boundaries of good taste on a Friday morning? ...

A rerun of "Quantum Leap" on NBC Wednesday night, with a 9.2 national Nielsen rating and an 18 share, outdrew a Barbara Walters special about "the perfect baby" on ABC, at 9.0/18, and the debut of "Top Cops" on CBS, at 8.8/17 between 10 and 11 ...

ABC's "Good Morning America" won for the 28th week in a row with a 4.4/23, compared with a 3.0/16 for NBC's "Today" show and a 2.3/12 for "CBS This Morning" ...

And the big news poolside this afternoon, TV Column fans? Los Angeles police have arrested two men believed to be part of a ring that has stolen 185 of the city's 40-pound manhole covers over the previous nine days ...