Find the invalid no.from the following series 3, 7, 15, 31 , 63, 127, 257 Choose the correct choice from the following:
A) 3
B) 7
C) 257
D) 63
E) 31
Go on multiplying the number by 2 and adding 1 to it to get the next number.So, 257 is wrong.   257
<result>C</result>
Find the invalid no.from the following series 3, 7, 15, 31 , 63, 127, 257