To solve this, compute strange(0) then strange(1) then strange(2) then strange(3) and finally strange(4).

  strange(0) = 2
  strange(1) = strange(0) + 3 = 5
  strange(2) = strange(1) + 3 = 8
  strange(3) = strange(2) + 3 = 11
  strange(4) = strange(3) + 3 = 14