| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 5 |
| 3 | 44 |
| 4 | 45 |
| 5 | 54 |
| 6 | 55 |
| 7 | 444 |
| 8 | 445 |
| 9 | 454 |
| 10 | 455 |
| 11 | 544 |
| 12 | 545 |
| 13 | 554 |
| 14 | 555 |
| 15 | 4444 |
| 16 | 4445 |
| 17 | 4454 |
| 18 | 4455 |
| 19 | 4544 |
| 20 | 4545 |
| 21 | 4554 |
| 22 | 4555 |
| 23 | 5444 |
| 24 | 5445 |
| 25 | 5454 |
| 26 | 5455 |
| 27 | 5544 |
| 28 | 5545 |
| 29 | 5554 |
| 30 | 5555 |
| 31 | 44444 |
| 32 | 44445 |
| 33 | 44454 |
| 34 | 44455 |
| 35 | 44544 |
| 36 | 44545 |
| 37 | 44554 |
| 38 | 44555 |
| 39 | 45444 |
| 40 | 45445 |
| 41 | 45454 |
| 42 | 45455 |
| 43 | 45544 |
[4,5,44,45,54,55,444,445,454,455,544,545,554,555, 4444,4445,4454,4455,4544,4545,4554,4555,5444,5445, 5454,5455,5544,5545,5554,5555,44444,44445,44454, 44455,44544,44545,44554,44555,45444,45445,45454, 45455,45544] |