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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 29 |
| 5 | 93 |
| 6 | 310 |
| 7 | 1106 |
| 8 | 4205 |
| 9 | 16912 |
| 10 | 71858 |
| 11 | 321921 |
| 12 | 1516429 |
| 13 | 7493126 |
| 14 | 38758968 |
| 15 | 209453249 |
| 16 | 1180293354 |
| 17 | 6923457745 |
| 18 | 42206892713 |
| 19 | 267002169884 |
| 20 | 1750266527588 |
| 21 | 11873506488390 |
| 22 | 83253781992093 |
| 23 | 602667751464027 |
[1,1,4,10,29,93,310,1106,4205,16912,71858,321921, 1516429,7493126,38758968,209453249,1180293354, 6923457745,42206892713,267002169884,1750266527588, 11873506488390,83253781992093,602667751464027] |