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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 29 |
| 5 | 133 |
| 6 | 658 |
| 7 | 3471 |
| 8 | 19400 |
| 9 | 114417 |
| 10 | 709815 |
| 11 | 4619048 |
| 12 | 31446579 |
| 13 | 223419752 |
| 14 | 1652599036 |
| 15 | 12698380493 |
| 16 | 101151995810 |
| 17 | 833740791381 |
| 18 | 7098646227614 |
| 19 | 62335051895044 |
| 20 | 563749889969108 |
| 21 | 5244173616702347 |
| 22 | 50117689766439784 |
[1,1,2,7,29,133,658,3471,19400,114417,709815, 4619048,31446579,223419752,1652599036,12698380493, 101151995810,833740791381,7098646227614, 62335051895044,563749889969108,5244173616702347, 50117689766439784] |