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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 30 |
| 6 | 98 |
| 7 | 328 |
| 8 | 1193 |
| 9 | 4459 |
| 10 | 17287 |
| 11 | 68283 |
| 12 | 274726 |
| 13 | 1118960 |
| 14 | 4607578 |
| 15 | 19135274 |
| 16 | 80063095 |
| 17 | 337104367 |
| 18 | 1427274619 |
| 19 | 6072510001 |
| 20 | 25949049372 |
| 21 | 111319539096 |
| 22 | 479243000380 |
| 23 | 2069825207344 |
| 24 | 8965693829582 |
| 25 | 38940393808337 |
| 26 | 169546919220357 |
| 27 | 739895248735963 |
[1,2,4,11,30,98,328,1193,4459,17287,68283,274726, 1118960,4607578,19135274,80063095,337104367, 1427274619,6072510001,25949049372,111319539096, 479243000380,2069825207344,8965693829582, 38940393808337,169546919220357,739895248735963] |