I'll give you a sequence of initials. You give the initials that logically follow: JFK / DDE / HST

The sequence of initials represents United States presidents in reverse chronological order. The series begins with John F. Kennedy (JFK), the 35th president, who served from 1961 until his assassination in 1963. Before him was Dwight D. Eisenhower (DDE), the 34th president, who was in office from 1953 to 1961. The next initials belong to the 33rd president, Harry S. Truman (HST), who led the country from 1945 to 1953.

Following this pattern, the correct initials are those of the 32nd president, Franklin Delano Roosevelt (FDR). Roosevelt's presidency was one of the most consequential in American history. He served from 1933 until his death in 1945, making him the longest-serving president in U.S. history and the only one to be elected four times. His tenure was marked by the immense challenges of the Great (Review) Depression and World War II.

The use of three-letter acronyms to refer to presidents became a common practice in the 20th century. Franklin D. Roosevelt was a trendsetter in this regard, with "FDR" becoming a widely recognized shorthand for the president. This tradition continued with successors like JFK and Lyndon B. Johnson (LBJ), whose initials became convenient identifiers in headlines and public conversation.