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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 45 |
| 6 | 141 |
| 7 | 463 |
| 8 | 1563 |
| 9 | 5364 |
| 10 | 18737 |
| 11 | 66410 |
| 12 | 238088 |
| 13 | 861872 |
| 14 | 3145644 |
| 15 | 11564752 |
| 16 | 42791022 |
| 17 | 159184950 |
| 18 | 595039609 |
| 19 | 2234155149 |
| 20 | 8420557767 |
| 21 | 31846117947 |
| 22 | 120823458983 |
| 23 | 459696946312 |
| 24 | 1753484378777 |
| 25 | 6704441257002 |
| 26 | 25689464721910 |
| 27 | 98628288008785 |
| 28 | 379353133321902 |
| 29 | 1461549660613824 |
| 30 | 5639706903125238 |
[1,1,2,5,15,45,141,463,1563,5364,18737,66410, 238088,861872,3145644,11564752,42791022,159184950, 595039609,2234155149,8420557767,31846117947, 120823458983,459696946312,1753484378777, 6704441257002,25689464721910,98628288008785, 379353133321902,1461549660613824,5639706903125238] |