Below is a portion of an AI answer:
"The numerical designations for fighter planes follow a specific system used by the U.S. military. The first letter in the designation, such as "F" for Fighter, indicates the basic mission of the aircraft. The number that follows is the design number, which is not necessarily sequential but indicates the aircraft's design in that mission category. For example, the F-15, F-16, and F-18 are fighter aircraft designed in that order under the fighter mission category. However, there are exceptions where the sequence is not strictly followed. For instance, the F-117 was not the 117th fighter design, but rather a stealth fighter that was given a higher number to emphasize its unique capabilities"
The last "F" aircraft introduced was the F-35 which got that designation partially because it was the X-35 in development. It was in the "30" series as it represented a new generation of design. This new plane is a "6th generation fighter", so it is appropriate that is is in the "40" series indicating yet another generation.
So the designation F-47 is not that unusual. Of course, the Pentagon could have designated it the F-45. It has been in development since the previous Trump administration.
BTW, the P-47 was in the "Pursuit" class of aircraft. It used a massive R-2800 'Double Wasp' engine that was also used in medium twin-engine bombers. The P-47 was used in dual roles as both a fighter and a ground-attack bomber. It could carry 2500 lbs of bombs and rockets under its wings. It was known to be able to withstand a massive amount of damage and keep flying.