Find the odd number out in the sequence: 1, 4, 9, 16, 23, 25, 36.

Problem restatement
Among 1, 4, 9, 16, 23, 25, 36, identify the unique term that does not share the core property of the others.

Given data

• Sequence: 1, 4, 9, 16, 23, 25, 36

Concept / Approach
These are mostly perfect squares of consecutive integers.

Step-by-step validation
1 = 1² 4 = 2² 9 = 3² 16 = 4² 23 ≠ n² for integer n 25 = 5² 36 = 6²

All are perfect squares except 23.

Verification / Alternative
Note that 23 lies strictly between 4²=16 and 5²=25, so it cannot be a perfect square.

Common pitfalls

• Misreading 23 as 6² (which is 36), or assuming it fits the square pattern.

Final Answer
23