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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 9 |
| 4 | 21 |
| 5 | 40 |
| 6 | 100 |
| 7 | 225 |
| 8 | 482 |
| 9 | 1119 |
| 10 | 2513 |
| 11 | 5565 |
| 12 | 12636 |
| 13 | 28376 |
| 14 | 63481 |
| 15 | 143118 |
| 16 | 321483 |
| 17 | 721413 |
| 18 | 1622729 |
| 19 | 3645740 |
| 20 | 8188668 |
| 21 | 18406009 |
| 22 | 41355654 |
| 23 | 92914375 |
| 24 | 208799157 |
| 25 | 469157625 |
| 26 | 1054150840 |
| 27 | 2368736000 |
| 28 | 5322460497 |
| 29 | 11959337226 |
[1,2,3,9,21,40,100,225,482,1119,2513,5565,12636, 28376,63481,143118,321483,721413,1622729,3645740, 8188668,18406009,41355654,92914375,208799157, 469157625,1054150840,2368736000,5322460497, 11959337226] |