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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 7 |
| 7 | 18 |
| 8 | 43 |
| 9 | 93 |
| 10 | 266 |
| 11 | 702 |
| 12 | 1687 |
| 13 | 5136 |
| 14 | 14405 |
| 15 | 36898 |
| 16 | 117016 |
| 17 | 341842 |
| 18 | 914064 |
| 19 | 2983027 |
| 20 | 8972121 |
| 21 | 24743851 |
| 22 | 82478973 |
| 23 | 253555061 |
| 24 | 715745648 |
| 25 | 2424954125 |
| 26 | 7582390623 |
| 27 | 21796481477 |
| 28 | 74805170349 |
| 29 | 237095926682 |
| 30 | 691568408221 |
| 31 | 2398418942361 |
| 32 | 7686495623620 |
[1,1,1,2,4,7,18,43,93,266,702,1687,5136,14405, 36898,117016,341842,914064,2983027,8972121, 24743851,82478973,253555061,715745648,2424954125, 7582390623,21796481477,74805170349,237095926682, 691568408221,2398418942361,7686495623620] |