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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 13 |
| 4 | 42 |
| 5 | 138 |
| 6 | 491 |
| 7 | 1691 |
| 8 | 6506 |
| 9 | 24158 |
| 10 | 95110 |
| 11 | 359634 |
| 12 | 1476071 |
| 13 | 5814658 |
| 14 | 24038501 |
| 15 | 95389250 |
| 16 | 405330287 |
| 17 | 1652139456 |
| 18 | 7033071180 |
| 19 | 28753343889 |
| 20 | 124893383967 |
| 21 | 520653084842 |
| 22 | 2260016606059 |
| 23 | 9429634274366 |
| 24 | 41586641260308 |
| 25 | 176164600968080 |
| 26 | 775437292036982 |
| 27 | 3283769720054476 |
| 28 | 14645257640355143 |
[1,2,5,13,42,138,491,1691,6506,24158,95110,359634, 1476071,5814658,24038501,95389250,405330287, 1652139456,7033071180,28753343889,124893383967, 520653084842,2260016606059,9429634274366, 41586641260308,176164600968080,775437292036982, 3283769720054476,14645257640355143] |