Answer:
229376
Step-by-step explanation:
So we can model the sequence of 1,2,4,8,16,32,... as [tex] 2^{n-1}[/tex] where n = 1,2,3,...
n = 16th, 17th, 18th then the terms are
[tex]2^{15} = 32768[/tex]
[tex]2^{16} = 65536[/tex]
[tex]2^{17} = 131072[/tex]
So the sum of the 3 terms is 32768 + 65536 + 131072 = 229376