A098783 Smallest number not occurring earlier such that the concatenation of the numbers has the property that the first two digits sum to 9, the next two to 9, the next two to 9, the next two to 9, etc.

0, 9, 1, 8, 2, 7, 3, 6, 4, 5, 18, 27, 36, 45, 54, 63, 72, 81, 90, 180, 91, 80, 92, 70, 93, 60, 94, 50, 95, 40, 96, 30, 97, 20, 98, 10, 909, 181, 82, 71, 83, 61, 84, 51, 85, 41, 86, 31, 87, 21, 88, 11, 809, 182, 73, 62, 74, 52, 75, 42, 76, 32, 77, 22, 78, 12, 709, 183, 64, 53, 65