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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 18 |
| 5 | 51 |
| 6 | 155 |
| 7 | 506 |
| 8 | 1627 |
| 9 | 5553 |
| 10 | 19155 |
| 11 | 66805 |
| 12 | 240211 |
| 13 | 863960 |
| 14 | 3165182 |
| 15 | 11733955 |
| 16 | 43652243 |
| 17 | 164830834 |
| 18 | 624894684 |
| 19 | 2385717893 |
| 20 | 9190397204 |
| 21 | 35493497563 |
| 22 | 138120244600 |
| 23 | 539990789121 |
| 24 | 2118183372082 |
| 25 | 8359695002728 |
| 26 | 33079605209574 |
| 27 | 131427000239706 |
| 28 | 524324934717073 |
| 29 | 2096414972054403 |
[1,1,3,6,18,51,155,506,1627,5553,19155,66805, 240211,863960,3165182,11733955,43652243,164830834, 624894684,2385717893,9190397204,35493497563, 138120244600,539990789121,2118183372082, 8359695002728,33079605209574,131427000239706, 524324934717073,2096414972054403] |