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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 10 |
| 3 | 36 |
| 4 | 133 |
| 5 | 501 |
| 6 | 1918 |
| 7 | 7440 |
| 8 | 29180 |
| 9 | 115522 |
| 10 | 461044 |
| 11 | 1852938 |
| 12 | 7492846 |
| 13 | 30464306 |
| 14 | 124461782 |
| 15 | 510696350 |
| 16 | 2103708187 |
| 17 | 8696498477 |
| 18 | 36066269640 |
| 19 | 150015248758 |
| 20 | 625664295594 |
| 21 | 2615929689642 |
| 22 | 10962436020878 |
| 23 | 46037427169060 |
[1,3,10,36,133,501,1918,7440,29180,115522,461044, 1852938,7492846,30464306,124461782,510696350, 2103708187,8696498477,36066269640,150015248758, 625664295594,2615929689642,10962436020878, 46037427169060] |