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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 17 |
| 3 | 154 |
| 4 | 1066 |
| 5 | 6370 |
| 6 | 34748 |
| 7 | 178296 |
| 8 | 875976 |
| 9 | 4167669 |
| 10 | 19348175 |
| 11 | 88112310 |
| 12 | 395137470 |
| 13 | 1749894510 |
| 14 | 7669512840 |
| 15 | 33323053200 |
| 16 | 143720109360 |
| 17 | 615950596170 |
| 18 | 2625443201394 |
| 19 | 11137650267156 |
| 20 | 47051359045460 |
| 21 | 198038873490436 |
| 22 | 830820684414952 |
[0,1,17,154,1066,6370,34748,178296,875976,4167669, 19348175,88112310,395137470,1749894510,7669512840, 33323053200,143720109360,615950596170, 2625443201394,11137650267156,47051359045460, 198038873490436,830820684414952] |