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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 6 |
| 3 | 44 |
| 4 | 46 |
| 5 | 64 |
| 6 | 66 |
| 7 | 444 |
| 8 | 446 |
| 9 | 464 |
| 10 | 466 |
| 11 | 644 |
| 12 | 646 |
| 13 | 664 |
| 14 | 666 |
| 15 | 4444 |
| 16 | 4446 |
| 17 | 4464 |
| 18 | 4466 |
| 19 | 4644 |
| 20 | 4646 |
| 21 | 4664 |
| 22 | 4666 |
| 23 | 6444 |
| 24 | 6446 |
| 25 | 6464 |
| 26 | 6466 |
| 27 | 6644 |
| 28 | 6646 |
| 29 | 6664 |
| 30 | 6666 |
| 31 | 44444 |
| 32 | 44446 |
| 33 | 44464 |
| 34 | 44466 |
| 35 | 44644 |
| 36 | 44646 |
| 37 | 44664 |
| 38 | 44666 |
| 39 | 46444 |
| 40 | 46446 |
| 41 | 46464 |
| 42 | 46466 |
| 43 | 46644 |
| 44 | 46646 |
[4,6,44,46,64,66,444,446,464,466,644,646,664,666, 4444,4446,4464,4466,4644,4646,4664,4666,6444,6446, 6464,6466,6644,6646,6664,6666,44444,44446,44464, 44466,44644,44646,44664,44666,46444,46446,46464, 46466,46644,46646] |