Number series – find the next two terms: 9, 11, 33, 13, 15, 33, 17, ?, ?

Introduction / Context:
This sequence alternates between a simple +2 progression and a constant “separator” value that repeats every third term.

Given Data / Assumptions:

• Series: 9, 11, 33, 13, 15, 33, 17, ?, ?
• Every third term appears to be the same constant.
• Non-constant positions increase by +2.

Concept / Approach:

Split into two interleaved sequences: (odd, odd, constant). Odd-position terms 1, 4, 7, … form a +2 sequence; every third term (3, 6, 9, …) equals 33.

Step-by-Step Solution:

Verification / Alternative check:

Check earlier: 9, 11, 33, 13, 15, 33, 17 … pattern holds perfectly.

Why Other Options Are Wrong:

33 35 or 33 19 invert the required order; 15 33 repeats older terms; 19 21 breaks the fixed 33 at every third position.

Common Pitfalls:

Not recognizing the periodic constant; always inspect every third term for repetition.

Final Answer:

19 33