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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 7 |
| 2 | 37 |
| 3 | 174 |
| 4 | 771 |
| 5 | 3300 |
| 6 | 13820 |
| 7 | 57044 |
| 8 | 233108 |
| 9 | 945793 |
| 10 | 3817351 |
| 11 | 15347362 |
| 12 | 61520899 |
| 13 | 246052888 |
| 14 | 982365976 |
| 15 | 3916739872 |
| 16 | 15599504614 |
| 17 | 62076995998 |
| 18 | 246866382826 |
| 19 | 981218764540 |
| 20 | 3898442536366 |
| 21 | 15483778158792 |
| 22 | 61482966826992 |
[1,7,37,174,771,3300,13820,57044,233108,945793, 3817351,15347362,61520899,246052888,982365976, 3916739872,15599504614,62076995998,246866382826, 981218764540,3898442536366,15483778158792, 61482966826992] |