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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 5 |
| 4 | 23 |
| 5 | 123 |
| 6 | 700 |
| 7 | 4170 |
| 8 | 25677 |
| 9 | 162101 |
| 10 | 1043603 |
| 11 | 6825429 |
| 12 | 45222437 |
| 13 | 302892681 |
| 14 | 2047499720 |
| 15 | 13950769772 |
| 16 | 95710823820 |
| 17 | 660609751890 |
| 18 | 4584018016679 |
| 19 | 31960334260971 |
| 20 | 223782306725768 |
| 21 | 1572921720684820 |
| 22 | 11094267854522250 |
| 23 | 78499108540111380 |
| 24 | 557041048588402170 |
[1,1,5,23,123,700,4170,25677,162101,1043603, 6825429,45222437,302892681,2047499720,13950769772, 95710823820,660609751890,4584018016679, 31960334260971,223782306725768,1572921720684820, 11094267854522250,78499108540111380, 557041048588402170] |