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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 2 |
| 3 | 4 |
| 4 | 7 |
| 5 | 12 |
| 6 | 22 |
| 7 | 77 |
| 8 | 142 |
| 9 | 532 |
| 10 | 1881 |
| 11 | 6680 |
| 12 | 23965 |
| 13 | 163600 |
| 14 | 576849 |
| 15 | 3866824 |
| 16 | 26635009 |
| 17 | 176366633 |
| 18 | 1204710337 |
| 19 | 15393505413 |
| 20 | 104674234457 |
| 21 | 1334666498849 |
| 22 | 17456897665295 |
| 23 | 221752333314343 |
| 24 | 2885843552520634 |
| 25 | 70795502834846238 |
[1,2,2,4,7,12,22,77,142,532,1881,6680,23965, 163600,576849,3866824,26635009,176366633, 1204710337,15393505413,104674234457,1334666498849, 17456897665295,221752333314343,2885843552520634, 70795502834846238] |