Artist Andy Warhol has at least an 18 1/2-minute gap in the tape recordings he made at the Democratic National Convention, and he suspects the White House.

More specifically, he suspects some James Bondian agent of the Secret Service, but he isn't the least bit mad at them.

"They're so GLAMOROUS, those people," he says, "with all their SOPHISTICATED electronics equipment."

Warhol is a pal of President Carter's mother, Miss Lillian, and was following her around New York with his cassettes whirling away. Carter aides who overheard some of the things she was saying were trying without success to find a way to push her "off" button.

When attempts to shush her didn't work, more desperate measures were deemed necessary.

There are conflicting versions about what happened and exactly how it happened, but everyone agrees some mysterious power took control of Warhol's tape recorde and all sorts of caustic comments from Miss Lillian about the Carter family's friends and foes are now lost for posterity.

Warhol told friends he first became aware that something was wrong when he and artist LeRoy Neiman got on an elevator with "Miss Lillian" at the Sheraton Centre.

She was chattering away faster than ot takes to zoom from the lobby to the 21st floor.

Warhol pushed his "record" button to capture those magical moments, and nothing happened.

He claims some kind of a "secret ray" jammed the recorder as long as her remained in Miss Lillian's presence. Away from her, he says, the recorder worked as always.

But that's not how the Carter people are telling it.

With glee, they claim that the Secret Service erased the tapes without ever touching them or Warhol.

A Secret Service spokesman denied yesterday that they had either "jammed" or erased" Warhol's tapes.

"We don't do that," the spokesman said. "You identify the agent that is supposed to have done it and we'll give him something -- and it won't be a medal."

Technologically, nothing could have been simpler.

Carmine Pellosie, vice president of Communications Control Systems, said yesterday that a powerful electromagnet small enough to fit into a woman's purse or a man's inside coat pocket can scramble or erase segments of tape in proximity in a matter of six to 10 seconds.

"You have noi way of knowing, there's no sound, no sensation, nothing" he said.

Also, nullifier, only recently made small enough to be portable, can erase an entire tape, he said, by sending out a low-range signal that messes up the sound and input circuitry.

Whatever happened to Miss Lillian's remarks, they are gone forever.

Warhol can't even reconstruct them with pencil and paper form memory.

"Andy has a lousy memory," Bob Colacello, executive editor of Warhol's Interview magazine, said yesterday. "Why do you think he carries that tape recorder?"