The number sequence puzzle
✓ With solution
A sequence that grows fast. Find the rule and the next number.
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Question 1
What comes next: 3, 5, 9, 17, 33, …?
- A49
- B63
- C65
- D66
Show the answer
Answer: C) 65. Each number is double the one before, minus 1: 3 × 2 − 1 = 5, 5 × 2 − 1 = 9, and so on up to 33 × 2 − 1 = 65. You can also spot it from the gaps: 2, 4, 8, 16, so the next gap is 32, and 33 + 32 = 65.
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