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| n | a(n) |
|---|---|
| 0 | -1 |
| 1 | -1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 3 |
| 5 | 5 |
| 6 | -1 |
| 7 | 7 |
| 8 | -1 |
| 9 | -1 |
| 10 | 9 |
| 11 | 11 |
| 12 | -1 |
| 13 | 13 |
| 14 | -1 |
| 15 | -1 |
| 16 | -1 |
| 17 | 17 |
| 18 | -1 |
| 19 | 19 |
| 20 | -1 |
| 21 | -1 |
| 22 | 21 |
| 23 | 23 |
| 24 | 23 |
| 25 | 13 |
| 26 | -1 |
| 27 | 23 |
| 28 | -1 |
| 29 | 29 |
| 30 | -1 |
| 31 | 31 |
| 32 | -1 |
| 33 | -1 |
| 34 | 33 |
| 35 | -1 |
| 36 | -1 |
| 37 | 37 |
| 38 | -1 |
| 39 | -1 |
| 40 | -1 |
| 41 | 41 |
| 42 | 41 |
| 43 | 43 |
| 44 | -1 |
| 45 | -1 |
| 46 | 39 |
| 47 | 47 |
| 48 | 41 |
| 49 | -1 |
| 50 | -1 |
| 51 | 47 |
| 52 | 37 |
| 53 | 53 |
| 54 | -1 |
| 55 | 43 |
| 56 | 47 |
| 57 | -1 |
| 58 | 57 |
| 59 | 59 |
| 60 | 47 |
| 61 | 61 |
| 62 | -1 |
| 63 | -1 |
| 64 | -1 |
| 65 | -1 |
| 66 | -1 |
[-1,-1,2,3,3,5,-1,7,-1,-1,9,11,-1,13,-1,-1,-1,17, -1,19,-1,-1,21,23,23,13,-1,23,-1,29,-1,31,-1,-1, 33,-1,-1,37,-1,-1,-1,41,41,43,-1,-1,39,47,41,-1, -1,47,37,53,-1,43,47,-1,57,59,47,61,-1,-1,-1,-1, -1] |