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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 10 |
| 4 | 58 |
| 5 | 334 |
| 6 | 1910 |
| 7 | 10910 |
| 8 | 62314 |
| 9 | 355898 |
| 10 | 2032630 |
| 11 | 11608866 |
| 12 | 66301138 |
| 13 | 378662314 |
| 14 | 2162634690 |
| 15 | 12351344662 |
| 16 | 70541601526 |
| 17 | 402880631914 |
| 18 | 2300951495750 |
| 19 | 13141306298158 |
| 20 | 75053268849534 |
| 21 | 428647886076278 |
| 22 | 2448114693124250 |
[0,2,10,58,334,1910,10910,62314,355898,2032630, 11608866,66301138,378662314,2162634690, 12351344662,70541601526,402880631914, 2300951495750,13141306298158,75053268849534, 428647886076278,2448114693124250] |