Find the invalid no.from the following series 3, 7, 15, 31, 61, 127, 255 Choose the correct choice from the following choices:
A) 3  B) 61  C) 27  D) 63  E) 127
Go on multiplying the number by 2 and adding 1 to it to get the next number.So, 61 is wrong.   61
<result>B</result>
Find the invalid no.from the following series 3, 7, 15, 31, 61, 127, 255