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Question 210046
JEE Mathematics · Hard

Sequences and Series: Recurrence MCQ

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RecurrenceHardQuestion 210046

Question

If aₙ₊₁ = 2aₙ + 1 and a₁ = 1, then a₅ is:
  1. A
    31
    Correct
  2. B
    15
  3. C
    63
  4. D
    7

Correct answer

31

Explanation

a₁=1, a₂=3, a₃=7, a₄=15, a₅=31. The closed form is aₙ = 2ⁿ − 1.

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