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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 10 |
| 3 | 55 |
| 4 | 487 |
| 5 | 4654 |
| 6 | 51463 |
| 7 | 632125 |
| 8 | 8536492 |
| 9 | 125279785 |
| 10 | 1981246555 |
| 11 | 33530245984 |
| 12 | 603797462677 |
| 13 | 11513675558701 |
| 14 | 231539488842610 |
| 15 | 4893151984630579 |
| 16 | 108334206855000739 |
| 17 | 2505977899186557502 |
| 18 | 60419653270442268643 |
| 19 | 1515077412621445514089 |
| 20 | 39437350309301393464876 |
| 21 | 1063746973172416765272589 |
[1,1,10,55,487,4654,51463,632125,8536492, 125279785,1981246555,33530245984,603797462677, 11513675558701,231539488842610,4893151984630579, 108334206855000739,2505977899186557502, 60419653270442268643,1515077412621445514089, 39437350309301393464876,1063746973172416765272589] |