John Adams is one of them.
find a counterexample to the statement all us presidents have served only one term to show statement is false
George Washington is the president that appointed the most Supreme Court Justices. There have been only seven US Presidents that served only one term.
27 of the 44 US presidents served more than one term in office. 19 of these were elected to more than one term in office. The other 8 served out the term of a president who died in office and were re-elected for a second full term. Only one president served more than two terms, Franklin D Roosevelt, who served three full terms and was elected for a fourth but died in office before finishing that term.
There were 40 presidents from 1789 to 1990. (Grover Cleveland served twice, I count him one; counting this way, George Bush was the 40th, who had started his term 1989.)
Only one and that was Franklin Roosevelt.
William Henry Harrison and James Garfield both died before they finished one year as President.
During Thomas Jefferson's first term, the Vice President was Aaron Burr. Jefferson's second term as President was George Clinton's first term as Vice President (Clinton was one of the two U.S. Vice Presidents who served under two Presidents).
Five Republicans served exactly one full term Benjamin Harrison, William Howard Taft, Herbert Hoover, and George H. W. Bush ran for a second term and lost. than one term. Hayes did not run for a second term by his own choice. Ford served less than one term as did Garfield, Harding, Arthur and Andrew Johnson. Ford tried for a full term but lost. Garfield and Harding died during their first term. Arthur and Andrew Johnson were not nominated for a second term.
Woodrow Wilson was one
All of these presidents served more than one term except for Carter. Jimmy Carter was president from the years of 1977 to 1981.
Lyndon Johnson finished out JFK's term and served one full term. Richard Nixon served one full term, was reelected but resigned. Gerald Ford served less than 4 years (finishing Nixon's term ). Jimmy Carter--one term. Ronald Reagan--two. George Bush the Elder--one. Bill Clinton--two. George Bush the Younger--two. Barack Obama--currently in office as I write this, but expected to live to the end of a second term.