इस शृंखला में लुप्त (?) ज्ञात कीजिए। 3, 5, 9, ?, 33, 65………. A. 23 B. 21 C. 17 D. 15

Each term is a power of 2 plus 1: 2 + 1 = 3, 4 + 1 = 5, 8 + 1 = 9, 16 + 1 = 17, 32 + 1 = 33, 64 + 1 = 65 (equivalently, each term is twice the previous minus 1). The missing term is 17.