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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 3 |
| 3 | 7 |
| 4 | 46 |
| 5 | 193 |
| 6 | 963 |
| 7 | 4470 |
| 8 | 21367 |
| 9 | 100909 |
| 10 | 478924 |
| 11 | 2268405 |
| 12 | 10753173 |
| 13 | 50957032 |
| 14 | 241508575 |
| 15 | 1144553203 |
| 16 | 5424374574 |
| 17 | 25707458901 |
| 18 | 121834519567 |
| 19 | 577405414054 |
| 20 | 2736475971043 |
| 21 | 12968875078785 |
| 22 | 61462896633780 |
[0,3,7,46,193,963,4470,21367,100909,478924, 2268405,10753173,50957032,241508575,1144553203, 5424374574,25707458901,121834519567,577405414054, 2736475971043,12968875078785,61462896633780] |