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| n | a(n) |
|---|---|
| 1 | 20 |
| 2 | 166 |
| 3 | 537 |
| 4 | 1358 |
| 5 | 3137 |
| 6 | 6838 |
| 7 | 14375 |
| 8 | 29416 |
| 9 | 58984 |
| 10 | 116466 |
| 11 | 227134 |
| 12 | 438532 |
| 13 | 839659 |
| 14 | 1596460 |
| 15 | 3017310 |
| 16 | 5673426 |
| 17 | 10619999 |
| 18 | 19801344 |
| 19 | 36791933 |
| 20 | 68149580 |
| 21 | 125882603 |
| 22 | 231941798 |
| 23 | 426388234 |
| 24 | 782226746 |
| 25 | 1432314394 |
| 26 | 2618121324 |
| 27 | 4778002317 |
[20,166,537,1358,3137,6838,14375,29416,58984, 116466,227134,438532,839659,1596460,3017310, 5673426,10619999,19801344,36791933,68149580, 125882603,231941798,426388234,782226746, 1432314394,2618121324,4778002317] |