Find odd one out in given sequence.13, 25, 51, 101, 203, 406

The correct answer is Option (3) → 406

Each term is double the one before, with 1 taken away and added by turns.

• \(13\times2-1=25\)

• \(25\times2+1=51\)

• \(51\times2-1=101\)

• \(101\times2+1=203\)

• \(203\times2-1=405\), but the series shows 406, so 406 does not fit