Wrong term in a x1+1, x2+2, x3+3 ... series

The same question, asked 2 times: 18 Sep 2025 S2*, 22 Sep 2025 S3. Every wording below, oldest first.

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Question 1
18 Sep 2025 S2
25 $The series given below contains a sequence of numbers. Accordingly identify the incorrect combination 6, 7, 16, 51, 210$
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Question 2
22 Sep 2025 S3
25 $The series given below contains a sequence of numbers. Accordingly identify the incorrect combination 4, 5, 12, 39, 163$
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