Which number does not belong in the following series: 1 – 2 – 5 – 10 – 13 – 26 – 29 – 38?

2 Answers

  • You’re alternately multiplying by 2 and adding 3:

    1 x 2 = 2, 2 + 3 = 5, 5 x 2 = 10, 10 + 3 = 13,

    13 x 2 = 26, 26 + 3 = 29 . . . so the next number

    should be 29 x 2 = 58

  • they are all negative numbers?

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