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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | -1 |
| 2 | 0 |
| 3 | 2 |
| 4 | 1 |
| 5 | -1 |
| 6 | 1 |
| 7 | 4 |
| 8 | 2 |
| 9 | -1 |
| 10 | 2 |
| 11 | 6 |
| 12 | 3 |
| 13 | -1 |
| 14 | 3 |
| 15 | 8 |
| 16 | 4 |
| 17 | -1 |
| 18 | 4 |
| 19 | 10 |
| 20 | 5 |
| 21 | -1 |
| 22 | 5 |
| 23 | 12 |
| 24 | 6 |
| 25 | -1 |
| 26 | 6 |
| 27 | 14 |
| 28 | 7 |
| 29 | -1 |
| 30 | 7 |
| 31 | 16 |
| 32 | 8 |
| 33 | -1 |
| 34 | 8 |
| 35 | 18 |
| 36 | 9 |
| 37 | -1 |
| 38 | 9 |
| 39 | 20 |
| 40 | 10 |
| 41 | -1 |
| 42 | 10 |
| 43 | 22 |
| 44 | 11 |
| 45 | -1 |
| 46 | 11 |
| 47 | 24 |
| 48 | 12 |
| 49 | -1 |
| 50 | 12 |
| 51 | 26 |
| 52 | 13 |
| 53 | -1 |
| 54 | 13 |
| 55 | 28 |
| 56 | 14 |
| 57 | -1 |
| 58 | 14 |
| 59 | 30 |
| 60 | 15 |
| 61 | -1 |
| 62 | 15 |
| 63 | 32 |
| 64 | 16 |
| 65 | -1 |
| 66 | 16 |
| 67 | 34 |
| 68 | 17 |
| 69 | -1 |
| 70 | 17 |
| 71 | 36 |
| 72 | 18 |
| 73 | -1 |
| 74 | 18 |
| 75 | 38 |
| 76 | 19 |
| 77 | -1 |
| 78 | 19 |
| 79 | 40 |
| 80 | 20 |
| 81 | -1 |
| 82 | 20 |
| 83 | 42 |
| 84 | 21 |
| 85 | -1 |
| 86 | 21 |
| 87 | 44 |
| 88 | 22 |
| 89 | -1 |
| 90 | 22 |
| 91 | 46 |
| 92 | 23 |
[0,-1,0,2,1,-1,1,4,2,-1,2,6,3,-1,3,8,4,-1,4,10,5, -1,5,12,6,-1,6,14,7,-1,7,16,8,-1,8,18,9,-1,9,20, 10,-1,10,22,11,-1,11,24,12,-1,12,26,13,-1,13,28, 14,-1,14,30,15,-1,15,32,16,-1,16,34,17,-1,17,36, 18,-1,18,38,19,-1,19,40,20,-1,20,42,21,-1,21,44, 22,-1,22,46,23] |