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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 72 |
| 6 | 220 |
| 7 | 590 |
| 8 | 1409 |
| 9 | 3055 |
| 10 | 6118 |
| 11 | 11474 |
| 12 | 20373 |
| 13 | 34542 |
| 14 | 56304 |
| 15 | 88714 |
| 16 | 135713 |
| 17 | 202301 |
| 18 | 294730 |
| 19 | 420718 |
| 20 | 589685 |
| 21 | 813012 |
| 22 | 1104324 |
| 23 | 1479798 |
| 24 | 1958497 |
| 25 | 2562731 |
| 26 | 3318446 |
| 27 | 4255642 |
| 28 | 5408821 |
| 29 | 6817466 |
| 30 | 8526552 |
[1,2,6,21,72,220,590,1409,3055,6118,11474,20373, 34542,56304,88714,135713,202301,294730,420718, 589685,813012,1104324,1479798,1958497,2562731, 3318446,4255642,5408821,6817466,8526552] |