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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 28 |
| 5 | 102 |
| 6 | 372 |
| 7 | 1392 |
| 8 | 5490 |
| 9 | 21848 |
| 10 | 88322 |
| 11 | 364457 |
| 12 | 1519209 |
| 13 | 6394726 |
| 14 | 27196992 |
| 15 | 116596476 |
| 16 | 503240096 |
| 17 | 2185814374 |
| 18 | 9549807525 |
| 19 | 41930059192 |
| 20 | 184918480762 |
| 21 | 819029864816 |
| 22 | 3641316550806 |
| 23 | 16243317238849 |
| 24 | 72693657655711 |
| 25 | 326286683303623 |
| 26 | 1468439616798464 |
| 27 | 6625361546600399 |
| 28 | 29962992825549341 |
[1,1,3,9,28,102,372,1392,5490,21848,88322,364457, 1519209,6394726,27196992,116596476,503240096, 2185814374,9549807525,41930059192,184918480762, 819029864816,3641316550806,16243317238849, 72693657655711,326286683303623,1468439616798464, 6625361546600399,29962992825549341] |