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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 51 |
| 5 | 212 |
| 6 | 1133 |
| 7 | 6001 |
| 8 | 36508 |
| 9 | 228435 |
| 10 | 1559575 |
| 11 | 11079180 |
| 12 | 83753497 |
| 13 | 659858617 |
| 14 | 5459331036 |
| 15 | 46980355355 |
| 16 | 421272977267 |
| 17 | 3917446787884 |
| 18 | 37766791690501 |
| 19 | 376447420971545 |
| 20 | 3875957531387172 |
| 21 | 41149332371734371 |
| 22 | 449984429580538407 |
| 23 | 5061923434006018612 |
| 24 | 58517321729774406129 |
[1,1,4,11,51,212,1133,6001,36508,228435,1559575, 11079180,83753497,659858617,5459331036, 46980355355,421272977267,3917446787884, 37766791690501,376447420971545,3875957531387172, 41149332371734371,449984429580538407, 5061923434006018612,58517321729774406129] |