Identify the single term that does not conform to the pattern in the following number series:

11, 75, 11, 136, 87, 303, 268

`. Let's format the solution carefully following all rules. 268

The correct option is 268.

To find the term that does not conform to the pattern, let us analyze the step-by-step mathematical operation between consecutive terms in the series.

The given number series is:
11, 75, 11, 136, 87, 303, 268

Let us observe the differences between successive terms:

1^st to 2^nd term:
$11+4^3=11+64=75$

2^nd to 3^rd term:
$75-8^2=75-64=11$

3^rd to 4^th term:
$11+5^3=11+125=136$

4^th to 5^th term:
$136-7^2=136-49=87$

5^th to 6^th term:
$87+6^3=87+216=303$

6^th to 7^th term:
Following the pattern of alternating addition of cubes of increasing numbers ($4^3,5^3,6^3$) and subtraction of squares of decreasing numbers ($8^2,7^2,6^2$), the next operation should be subtracting $6^2$:

$303-6^2=303-36=267$

However, the given series has 268 instead of 267.

Therefore, 268 is the term that does not conform to the pattern.