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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 30 |
| 2 | 464 |
| 3 | 4930 |
| 4 | 40454 |
| 5 | 273266 |
| 6 | 1581775 |
| 7 | 8064464 |
| 8 | 36943940 |
| 9 | 154385704 |
| 10 | 595514217 |
| 11 | 2140442150 |
| 12 | 7224301969 |
| 13 | 23043923160 |
| 14 | 69844600965 |
| 15 | 202081362622 |
| 16 | 560350431315 |
| 17 | 1494273031164 |
| 18 | 3843681391300 |
| 19 | 9562404542460 |
| 20 | 23062890166272 |
[1,30,464,4930,40454,273266,1581775,8064464, 36943940,154385704,595514217,2140442150, 7224301969,23043923160,69844600965,202081362622, 560350431315,1494273031164,3843681391300, 9562404542460,23062890166272] |