[
  "Let the smallest odd number be n. The three numbers: n, n+2, n+4. Sum = 3n + 6.",
  "The sum is also 15 more than twice the smallest: 3n + 6 = 2n + 15.",
  "Solve: n = 9. Check: 9 + 11 + 13 = 33, and 15 + 18 = 33. Matches."
]