Jelly, 6 bytes
BḄ-8ƤṀ
A monadic link taking a number and returning a number.
How?
Uses a nice quick , Ƥ, developed by miles ...
BḄ-8ƤṀ - Link: number
B - convert to a binary list
Ƥ - for loop over some slices to be determined...
-8 - this is a negative nilad, therefore: use overlapping outfixes of length 8
- (exactly what the specification asks us to inspect)
Ḅ - convert from a binary list to an integer (vectorises)
Ṁ - maximum
Jelly, 6 bytes
BḄ-8ƤṀ
A monadic link taking a number and returning a number.
How?
Uses a nice quick , Ƥ, developed by miles ...
BḄ-8ƤṀ - Link: number
B - convert to a binary list
Ƥ - for loop over some slices to be determined...
-8 - this is a negative nilad, therefore: use overlapping outfixes of length 8
- (exactly what the specification asks us to inspect)
Ḅ - convert from a binary list to an integer (vectorises)
Ṁ - maximum