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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 19 |
| 3 | 40 |
| 4 | 166 |
| 5 | 824 |
| 6 | 3256 |
| 7 | 15028 |
| 8 | 64156 |
| 9 | 275764 |
| 10 | 1203956 |
| 11 | 5186196 |
| 12 | 22489732 |
| 13 | 97426420 |
| 14 | 421553284 |
| 15 | 1826019284 |
| 16 | 7905435556 |
| 17 | 34229151412 |
| 18 | 148217266564 |
| 19 | 641745438100 |
| 20 | 2778733096676 |
| 21 | 12031672904052 |
| 22 | 52095855239236 |
[0,19,40,166,824,3256,15028,64156,275764,1203956, 5186196,22489732,97426420,421553284,1826019284, 7905435556,34229151412,148217266564,641745438100, 2778733096676,12031672904052,52095855239236] |