Which of these US presidents appeared on the television series "Laugh-In"?

"Laugh-In" is an American sketch comedy television program that ran for 140 episodes from January 22, 1968 to March 12, 1973. It launched the careers of numerous actors, especially women, including Goldie Hawn, Lily Tomlin and Ruth Buzzi. It introduced catch phrases like “sock it to me,” “verrrry interesting,” and “look that up in your Funk & Wagnalls.”

Perhaps the most long-lasting and influential moment in "Laugh-In’s" incredibly successful five-year run, however, was that cameo appearance by presidential candidate Richard M. Nixon in 1968.

It wasn’t very funny by modern standards, but Nixon’s stilted delivery of the show’s signature catchphrase “sock it to me” was part of a revolutionary effort to reach out to younger voters, taken against the advice of Nixon’s campaign managers.