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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 11 |
| 4 | 33 |
| 5 | 114 |
| 6 | 435 |
| 7 | 1828 |
| 8 | 8347 |
| 9 | 40967 |
| 10 | 213476 |
| 11 | 1167038 |
| 12 | 6620563 |
| 13 | 38616800 |
| 14 | 229908144 |
| 15 | 1389394409 |
| 16 | 8488437842 |
| 17 | 52275301038 |
| 18 | 323844494931 |
| 19 | 2015202856151 |
| 20 | 12583558074610 |
| 21 | 78792289312786 |
| 22 | 494476637793884 |
| 23 | 3109144620092506 |
[2,4,11,33,114,435,1828,8347,40967,213476,1167038, 6620563,38616800,229908144,1389394409,8488437842, 52275301038,323844494931,2015202856151, 12583558074610,78792289312786,494476637793884, 3109144620092506] |