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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 23 |
| 2 | 276 |
| 3 | 2299 |
| 4 | 14927 |
| 5 | 80454 |
| 6 | 374439 |
| 7 | 1545807 |
| 8 | 5771919 |
| 9 | 19781035 |
| 10 | 62936510 |
| 11 | 187603065 |
| 12 | 527817225 |
| 13 | 1410264780 |
| 14 | 3596907555 |
| 15 | 8795685646 |
| 16 | 20699124413 |
| 17 | 47031284166 |
| 18 | 103467710300 |
| 19 | 220946372920 |
| 20 | 458974273140 |
| 21 | 929305397041 |
[1,23,276,2299,14927,80454,374439,1545807,5771919, 19781035,62936510,187603065,527817225,1410264780, 3596907555,8795685646,20699124413,47031284166, 103467710300,220946372920,458974273140, 929305397041] |