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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 15 |
| 5 | 39 |
| 6 | 151 |
| 7 | 433 |
| 8 | 1709 |
| 9 | 5280 |
| 10 | 22022 |
| 11 | 71793 |
| 12 | 303871 |
| 13 | 1023620 |
| 14 | 4371400 |
| 15 | 15150011 |
| 16 | 65796555 |
| 17 | 233352833 |
| 18 | 1020880390 |
| 19 | 3682945922 |
| 20 | 16198234948 |
| 21 | 59334969586 |
| 22 | 262976270037 |
| 23 | 975960981965 |
| 24 | 4344603109223 |
| 25 | 16296038329083 |
| 26 | 72801064185198 |
| 27 | 275712621863626 |
| 28 | 1237070361773768 |
| 29 | 4725127985365837 |
[1,1,2,4,15,39,151,433,1709,5280,22022,71793, 303871,1023620,4371400,15150011,65796555, 233352833,1020880390,3682945922,16198234948, 59334969586,262976270037,975960981965, 4344603109223,16296038329083,72801064185198, 275712621863626,1237070361773768,4725127985365837] |