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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 24 |
| 4 | 99 |
| 5 | 407 |
| 6 | 1776 |
| 7 | 7835 |
| 8 | 35400 |
| 9 | 161472 |
| 10 | 746382 |
| 11 | 3474604 |
| 12 | 16300338 |
| 13 | 76908464 |
| 14 | 364715409 |
| 15 | 1736718508 |
| 16 | 8301812970 |
| 17 | 39807939808 |
| 18 | 191423730408 |
| 19 | 922824490028 |
| 20 | 4458571378237 |
| 21 | 21583898594952 |
| 22 | 104676864185763 |
| 23 | 508468611377079 |
| 24 | 2473498648120590 |
| 25 | 12048802278297781 |
| 26 | 58762633391661819 |
| 27 | 286908179389872434 |
[1,2,7,24,99,407,1776,7835,35400,161472,746382, 3474604,16300338,76908464,364715409,1736718508, 8301812970,39807939808,191423730408,922824490028, 4458571378237,21583898594952,104676864185763, 508468611377079,2473498648120590, 12048802278297781,58762633391661819, 286908179389872434] |