Mayor Marion Barry gave a pointed pep talk to students at Anacostia High School yesterday as part of a citywide effort to generate more applications for the city's summer jobs program, which has suffered as a result of cumbersome registration procedures.

Only about 13,000 D.C. youths have registered for summer jobs so far this year, according to a spokesman for the city's Department of Employment Services. By contrast, the spokesman said, more than 20,000 had registered by this time last year.

Barry told students at a morning assembly at the school, 16th and R streets SE, to register for the jobs program because "anything worth having is worth working for."

The Anacostia students gave Barry a cool reception at first, welcoming him with scant applause, but later warmed to his frequent lighthearted lines.

"All you men out there, you want to make it with all these ladies?" the mayor asked. "Then you ought to go to work. You ladies don't want to go out with somebody who's broke, do you?"

The students, previously as stiff as mannequins, broke into animated laughter. They giggled, joked with each other in a momentary din that forced Barry to pause, and then many relaxed from their upright positions and slid into sterotypical teen-age slumps.

This year, for the first time, all applicants for the summer jobs program must be accompanied by parents or guardians when they register. In addition, they must bring proof of age, District of Columbia residency and family income -- the last being required to establish eligibility for those federally funded summer jobs reserved for low-income youths.

Officials said that these guidelines -- especially the requirement that parents come along -- have probably caused the lagging response.

"If these parents don't start coming out with their kids, we're in trouble," said employment department spokesman Adolph Slaughter, who estimated that at least 20,000 summer jobs will be available this year. Last year, there were 30,000 jobs according to city officials.

"You ought to tell your parents, 'You come down and apply with me, or you pay me this summer to stay home,'" Barry told the students.

"You've got to get into the habit of working. You'll never get something for nothing."

Afterward, the students seemed less interested in gathering around the mayor than in seeking autographs and advice on how to run a fast break from Washington Bullet guard Larry Wright, who also was on hand to push the jobs program.

Several students interviewed later said they were interested in applying for the summer jobs. But many students said they also were concerned about other issues, including proposed cuts in the school system's budget and the controversial legalized gambling referendum on the May 6 ballot.

Schools Superintendent Vincent E. Reed ahs proposed laying off 700 teachers and cutting back such programs as driver education and shop classes to help avoid a possible $26 million budget deficit.

"I don't see how they can take nothing from nothing," said 17-year-old Terence Green, a junior at the high school. "As far as the school budget goes, we don't have anything to begin with.

"You see that car?" Green asked, pointing to a tan driver education vehicle parked on the street in front of the school. "It's gone. Gone. You go out to those white schools in Maryland, and they have everything."

Darnell Butler, a 17-year-old senior, said he feared the proposed teacher layoffs would mean that elective classes, such as graphic arts and languages, would be eliminated.

"They should cut their own pay," Butler said of city officials. "They're cutting, all right but they're cutting the wrong things."

Green said he was opposed to the gambling initiative because he believed it would induce people to spend money they should use for necessities.

"What's going to happen to the black man?" he asked. "He's going to be playing the lottery with his rent bill. There are going to be a lot of children around here who don't have a thing.

"And what makes it worse is it's going to be the black man who suffers."

According to the city's employment department, 17,500 city-funded and federally funded summer jobs will be available for youths from 14 to 21 years old. An additional 2,500 jobs have been pledged by the Greater Washington Board of Trade, with more private sector jobs expected.

Yersterday's presentation was the first of a series of assemblies scheduled at all the city's senior high schools to publicize the jobs program.