What should come in place of the question mark (?) in the following number series?
Successive powers of 2 are added
1 + $$2^2$$ = 5
5 + $$2^3$$ = 13
13 + $$2^4$$ = 29
29 + $$2^5$$ = 61
61 + $$2^6$$ = 125
125 + $$2^7$$ = 253
Create a FREE account and get: