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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 26 |
| 6 | 70 |
| 7 | 195 |
| 8 | 558 |
| 9 | 1578 |
| 10 | 4678 |
| 11 | 14067 |
| 12 | 42248 |
| 13 | 128588 |
| 14 | 399183 |
| 15 | 1241119 |
| 16 | 3873090 |
| 17 | 12243222 |
| 18 | 38947570 |
| 19 | 124009672 |
| 20 | 397559401 |
| 21 | 1283652201 |
| 22 | 4152226324 |
| 23 | 13472767649 |
| 24 | 43967385684 |
| 25 | 143918657309 |
| 26 | 471891799395 |
| 27 | 1553179013035 |
| 28 | 5129597538276 |
| 29 | 16968589795201 |
| 30 | 56263344975599 |
| 31 | 187121094027032 |
[1,1,2,4,11,26,70,195,558,1578,4678,14067,42248, 128588,399183,1241119,3873090,12243222,38947570, 124009672,397559401,1283652201,4152226324, 13472767649,43967385684,143918657309,471891799395, 1553179013035,5129597538276,16968589795201, 56263344975599,187121094027032] |