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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 13 |
| 5 | 40 |
| 6 | 119 |
| 7 | 376 |
| 8 | 1202 |
| 9 | 3916 |
| 10 | 12920 |
| 11 | 42974 |
| 12 | 143989 |
| 13 | 485623 |
| 14 | 1646056 |
| 15 | 5601850 |
| 16 | 19127858 |
| 17 | 65491001 |
| 18 | 224750426 |
| 19 | 772816118 |
| 20 | 2661800949 |
| 21 | 9180835248 |
| 22 | 31703037147 |
| 23 | 109586025511 |
| 24 | 379124973003 |
| 25 | 1312592051481 |
| 26 | 4547284385059 |
| 27 | 15761969520682 |
| 28 | 54660238286990 |
[1,1,2,5,13,40,119,376,1202,3916,12920,42974, 143989,485623,1646056,5601850,19127858,65491001, 224750426,772816118,2661800949,9180835248, 31703037147,109586025511,379124973003, 1312592051481,4547284385059,15761969520682, 54660238286990] |