An article at Bloomberg has revealed that the USAF will request eight F-15X fighters in its budget.
The service plans to buy 80 fighters over five years.
That's enough to fit out a wing of 72 aircraft, divided into three squadrons of 24 planes each, with eight spares.
That's just the five-year projection, though, and the service may buy additional fighters beyond 2025.
From Nutty's link.
Seems to be a good idea, in terms of "high-low mix" insofar as capability goes.