Find odd one out in the given series.

6, 24, 60, 120, 211, 336

211

The correct answer is Option 2: 211

Each number in this series follows the formula $n^3 - n$ (the cube of a natural number minus the number itself):

• $2^3 - 2 = 8 - 2 =$ 6

• $3^3 - 3 = 27 - 3 =$ 24

• $4^3 - 4 = 64 - 4 =$ 60

• $5^3 - 5 = 125 - 5 =$ 120

• $6^3 - 6 = 216 - 6 =$ 210 (But the series gives 211)

• $7^3 - 7 = 343 - 7 =$ 336