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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 6 |
| 3 | 42 |
| 4 | 114 |
| 5 | 654 |
| 6 | 2526 |
| 7 | 13506 |
| 8 | 61242 |
| 9 | 321558 |
| 10 | 1579830 |
| 11 | 8311578 |
| 12 | 42655938 |
| 13 | 226373406 |
| 14 | 1192341390 |
| 15 | 6391471794 |
| 16 | 34239385482 |
| 17 | 185275416102 |
| 18 | 1004459653734 |
| 19 | 5480384744202 |
| 20 | 29980061984274 |
| 21 | 164732303389614 |
| 22 | 907579024283454 |
[1,6,6,42,114,654,2526,13506,61242,321558,1579830, 8311578,42655938,226373406,1192341390,6391471794, 34239385482,185275416102,1004459653734, 5480384744202,29980061984274,164732303389614, 907579024283454] |