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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 19 |
| 5 | 61 |
| 6 | 201 |
| 7 | 672 |
| 8 | 2269 |
| 9 | 7723 |
| 10 | 26452 |
| 11 | 91058 |
| 12 | 314766 |
| 13 | 1091884 |
| 14 | 3798900 |
| 15 | 13251136 |
| 16 | 46325285 |
| 17 | 162268775 |
| 18 | 569385098 |
| 19 | 2001012474 |
| 20 | 7042014879 |
| 21 | 24813529581 |
| 22 | 87533417037 |
| 23 | 309107111536 |
| 24 | 1092585807044 |
| 25 | 3865270781236 |
[1,2,6,19,61,201,672,2269,7723,26452,91058,314766, 1091884,3798900,13251136,46325285,162268775, 569385098,2001012474,7042014879,24813529581, 87533417037,309107111536,1092585807044, 3865270781236] |